Vacuum packaging device and method for on-chip microsystem and vacuum packaged on-chip microsystem

Abstract

The invention provides a vacuum packaging device and method for an on-chip microsystem, and the vacuum packaged on-chip microsystem comprises an ultrafast laser generation device which is used for generating ultrafast laser for bonding; the closed chamber is used for accommodating a microsystem substrate and a cover plate substrate to be bonded; the first displacement table is used for supporting and moving the closed cavity; the second displacement table is used for moving a microsystem substrate and / or a cover plate substrate to be bonded, the position of the working part corresponds to the position of the concave cavity structure, and the second displacement table is also used for aligning, attaching and fixing the bonding parts of the microsystem substrate and the cover plate substrate; the vacuum system is connected with the closed chamber and is used for pumping the vacuum degree of the closed chamber to preset air pressure after the microsystem substrate and the cover plate substrate are arranged in the closed chamber; and the driving system is used for providing voltage driving for the ultrafast laser generating device, the first displacement table, the second displacement table and the vacuum system. According to the invention, the vacuum packaging of the on-chip microsystem under the room temperature condition can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of vacuum packaging for on-chip microsystems, and particularly to a vacuum packaging device and method for on-chip microsystems, and an on-chip microsystem with vacuum packaging. Background Art

[0002] The types of on-chip microsystems (System on Chip) include micro-electro-mechanical systems (MEMS) (such as MEMS gyroscopes, MEMS accelerometers, etc.), micro thermal imagers, and micro vacuum electronic devices, etc. The packaging of on-chip microsystems needs to be carried out in a vacuum or low-pressure environment to protect the working components or sensitive components of the on-chip microsystems from external influences and contamination, so as to achieve stable and ideal performance. Therefore, the wafer-level packaging technology for realizing the vacuum or low-pressure environment of on-chip microsystems is crucial.

[0003] The key to the wafer-level vacuum packaging technology for on-chip microsystems lies in realizing the airtight bonding of the microsystem wafer substrate and the cover wafer substrate in a vacuum environment, so as to construct a closed micro-vacuum chamber between the microsystem substrate and the cover substrate, enabling the working components of the microsystem (such as the mechanical moving components of MEMS, the heat-sensitive components of micro thermal imagers, the electronic emission components of micro vacuum electronic devices and systems, etc.) to be in a vacuum environment.

[0004] At present, the vacuum bonding technologies adopted for wafer-level vacuum packaging of on-chip microsystems include: (1) Anodic bonding technology (or electrostatic bonding technology) (Chinese patents: ZL200910262848.0, ZL 201010571925.3, ZL201210025120.8). Anodic bonding needs to be carried out under high voltage (generally greater than 1000V) and high temperature (generally greater than 300°C), and can achieve direct bonding of silicon-based substrates and glass-based substrates; (2) Fusion bonding technology (Chinese patents: ZL202311609406.5, ZL201210346195.6). Fusion bonding needs to be carried out at high temperature (generally greater than 1000°C), and can achieve direct bonding between silicon-based substrates, but has very high requirements for the flatness between the substrates; (3) Eutectic bonding technology (Chinese patents: ZL200910227989.9, ZL201010279475.0). By introducing a low-temperature eutectic alloy layer (such as Au / Si, Al / Ge / Si, etc.) at the bonding interface, heating and melting the eutectic alloy layer (generally greater than 300°C) and then cooling and solidifying to achieve interfacial bonding; (4) Solder bonding technology (Chinese patents: ZL201010166444.4, ZL201510075264.8, ZL201410270430.5). By introducing a solder layer (such as glass powder, tin, etc.) at the bonding interface, heating and melting the solder (generally greater than 300°C) and then cooling and solidifying to achieve interfacial bonding.

[0005] It can be seen that the existing vacuum packaging technologies have the following problems: (1) All bonding technologies need to be carried out under high-temperature conditions, and high temperature is extremely likely to damage temperature-sensitive modules such as sensor devices and CMOS integrated circuits of on-chip microsystems, greatly limiting their application scenarios; (2) Some technologies (eutectic bonding and solder bonding technologies) need to introduce an intermediate material layer at the bonding interface, increasing the process complexity and cost of processing; (3) The bonding technologies that do not require the introduction of an intermediate material layer (anodic bonding and fusion technologies) can achieve direct bonding of microsystem substrates and cover substrates, but the substrates that can be bonded are limited to very few material combinations such as silicon-glass, silicon-silicon, silicon nitride-silicon nitride, etc. In addition, the cost of vacuum packaging can account for 30%-70% of the cost of on-chip microsystems. By optimizing the wafer-level vacuum packaging technology of on-chip microsystems, the cost of on-chip microsystems can be significantly reduced.

[0006] Therefore, how to provide a device and method for realizing vacuum packaging of on-chip microsystems at room temperature conditions, and an on-chip microsystem with vacuum packaging to overcome the problems existing in the above existing vacuum packaging technologies is an urgent technical problem to be solved. Summary of the Invention

[0007] In view of this, embodiments of the present invention provide a vacuum packaging device and method for an on-chip microsystem, and an on-chip microsystem with vacuum packaging, so as to eliminate or improve one or more defects existing in the prior art.

[0008] One aspect of the present invention provides a vacuum packaging device for an on-chip microsystem. The vacuum packaging device includes: an ultrafast laser generating device for generating ultrafast laser for bonding; a sealed chamber for accommodating a microsystem substrate and a cover substrate to be bonded, the sealed chamber including a window for transmitting the ultrafast laser; a first displacement stage for supporting and moving the sealed chamber; a second displacement stage located inside the sealed chamber for moving the microsystem substrate and / or the cover substrate to be bonded, the position of the working component pre-processed on the microsystem substrate corresponding to the position of the cavity structure, and further for aligning, attaching and fixing the bonding parts of the microsystem substrate and the cover substrate; a vacuum system connected to the sealed chamber for pumping the vacuum degree of the sealed chamber to a preset air pressure after the microsystem substrate and the cover substrate are placed in the sealed chamber; and a driving system for providing voltage drive to the ultrafast laser generating device, the first displacement stage, the second displacement stage and the vacuum system.

[0009] In some embodiments of the present invention, the microsystem substrate and / or the cover substrate have a cavity structure for accommodating the working components of the on-chip microsystem, so that a microchamber is formed at the cavity structure after the microsystem substrate and the cover substrate are attached and fixed, and the working components of the on-chip microsystem are located inside the microchamber; the microsystem substrate and / or the cover substrate can transmit the ultrafast laser for bonding at least at the bonding parts; when the bonding parts of the microsystem substrate and the cover substrate are aligned, attached and fixed, a microchamber can be formed at the cavity structure, and the working components of the on-chip microsystem are located inside the microchamber.

[0010] In some embodiments of the present invention, the ultrafast laser generated by the ultrafast laser generating device is used to be focused at the bonding interface of the microsystem substrate and the cover substrate, and the focus of the ultrafast laser moves along the bonding interface, and the energy of the ultrafast laser is used to melt the materials of the microsystem substrate and the cover substrate near the focus, and after solidification, the bonding of the microsystem substrate and the cover substrate near the focus is realized.

[0011] In some embodiments of the present invention, the moving trajectory of the focus of the ultrafast laser surrounds the cavity structure at least once, so that the microchamber is sealed and the vacuum packaging of the on-chip microsystem is completed.

[0012] In some embodiments of the present invention, the vacuum packaging device further includes a heating device located above the second displacement stage. The heating device is used to heat the microsystem substrate and the cover substrate to be bonded to remove the gas molecules adsorbed on their surfaces, and the driving system is used to provide voltage drive to the heating device.

[0013] In some embodiments of the present invention, the vacuum packaging device further includes an air injection system. The air injection system is used to inject a specific type of atomic vapor into the vacuum chamber and stop injecting air when the concentration of the atomic vapor meets a preset condition, so that the microchamber formed at the concave cavity structure is filled with the atomic vapor of the preset type and concentration after the bonding parts of the microsystem substrate and the cover substrate are aligned, attached and fixed. The driving system is used to provide voltage drive to the air injection system.

[0014] In some embodiments of the present invention, the vacuum packaging device further includes a leveling device. The leveling device is installed between the first displacement stage and the vacuum chamber and is used to adjust the microsystem substrate and the cover substrate to be in a horizontal state.

[0015] In some embodiments of the present invention, the vacuum packaging device further includes a control system, which is used to control the working state of the ultrafast laser generating device, to control the moving direction and speed of the first displacement stage and the second displacement stage, and to control the working state of the vacuum system.

[0016] In some embodiments of the present invention, the material combinations on both sides of the bonding interface of the microsystem substrate and the cover substrate for bonding include: glass - silicon, glass - glass, quartz - silicon, quartz - quartz, glass - quartz, glass - metal, glass - ceramic, quartz - metal, and quartz - ceramic.

[0017] In some embodiments of the present invention, the microsystem substrate and the cover substrate are of wafer - level size and standard wafer shape.

[0018] In some embodiments of the present invention, the microsystem substrate and / or the cover substrate is a substrate composed of multiple layers of materials; or, the microsystem substrate and the cover substrate are substrates including through - holes and glass through - holes or silicon through - holes penetrating micro - electrodes.

[0019] In some embodiments of the present invention, when a plurality of working components are provided on the microsystem substrate to be bonded, and correspondingly, a plurality of concave cavities are included on the cover substrate, the moving trajectory of the focus of the ultrafast laser should surround each concave cavity structure at least once, so as to obtain a plurality of on - chip microsystems that have completed vacuum packaging at one time.

[0020] Correspondingly to the above method, the present invention further provides a vacuum-packaged on-chip microsystem, which realizes vacuum packaging based on the vacuum packaging method of the on-chip microsystem described in any one of the above embodiments.

[0021] Correspondingly to the above method, the present invention further provides a method for vacuum packaging an on-chip microsystem, including: placing a microsystem substrate and a cover substrate in a sealed chamber, and pumping the vacuum degree of the sealed chamber to a preset air pressure; wherein, the microsystem substrate and / or the cover substrate has a concave cavity structure for accommodating the working components of the on-chip microsystem, and the microsystem substrate and / or the cover substrate can transmit the ultrafast laser for bonding at least at the bonding site; the position of the working components pre-processed on the microsystem substrate corresponds to the position of the concave cavity structure, aligning, attaching and fixing the bonding sites of the microsystem substrate and the cover substrate, so as to form a microchamber at the concave cavity structure, and the working components of the on-chip microsystem are located in the microchamber; focusing the ultrafast laser at the bonding interface of the microsystem substrate and the cover substrate, controlling the focus of the ultrafast laser to move along the bonding interface, melting the materials of the microsystem substrate and the cover substrate near the focus by using the energy of the ultrafast laser, and realizing the bonding of the microsystem substrate and the cover substrate near the focus after curing; by making the moving trajectory of the focus of the ultrafast laser surround the concave cavity structure at least once, the microchamber is closed, and the vacuum packaging of the on-chip microsystem is completed.

[0022] In some embodiments of the present invention, before placing the microsystem substrate and the cover substrate in the sealed chamber, the method further includes: introducing a getter on the inner wall of the concave cavity structure of the microsystem substrate and / or the cover substrate; after the bonding of the microsystem substrate and the cover substrate is completed, the method further includes: heating the bonded substrates as a whole or locally heating the position where the getter is introduced to activate the getter, so that the getter adsorbs the residual gas in the microchamber formed at the concave cavity structure.

[0023] In some embodiments of the present invention, before aligning, attaching and fixing the bonding sites of the microsystem substrate and the cover substrate, the method further includes: a degassing step, by heating the microsystem substrate and the cover substrate as a whole to a preset temperature and maintaining the heating for a preset time to remove the gas adsorbed on the substrate surface.

[0024] In some embodiments of the present invention, after pumping the vacuum degree of the sealed chamber to the preset air pressure and before aligning, attaching and fixing the bonding sites of the microsystem substrate and the cover substrate, the method further includes: injecting an atomic vapor of a preset type into the sealed chamber until the concentration of the atomic vapor meets a preset condition, so that the microchamber formed at the concave cavity structure is filled with an atomic vapor of a preset type and concentration after aligning, attaching and fixing the bonding sites of the microsystem substrate and the cover substrate.

[0025] In some embodiments of the present invention, during the process of controlling the focus of the ultrafast laser to move along the bonding interface, the method further includes: using a leveling device to adjust the micro-system substrate and the cover substrate to be in a horizontal state.

[0026] In some embodiments of the present invention, when a plurality of working components are provided on the micro-system substrate to be bonded, and correspondingly, a plurality of cavities are included on the cover substrate, the movement trajectory of the focus of the ultrafast laser should surround each cavity structure at least once, so as to obtain a plurality of on-chip micro-systems with vacuum encapsulation completed at one time.

[0027] In some embodiments of the present invention, after obtaining a plurality of on-chip micro-systems with vacuum encapsulation completed at one time, the method further includes: a dicing step, dicing the already bonded micro-system substrate and the cover substrate to obtain each independent on-chip micro-system with vacuum encapsulation completed.

[0028] The vacuum encapsulation device and method for the on-chip micro-system proposed by the present invention can realize the vacuum encapsulation of the on-chip micro-system at room temperature, and there is no need for an intermediate material layer, and can be directly bonded, reducing the bonding process steps and costs, and greatly expanding the range of substrate materials applicable to vacuum encapsulation.

[0029] The additional advantages, objects, and features of the present invention will be partially described below, and will become partially apparent to those of ordinary skill in the art after studying the following text, or can be learned from the practice of the present invention. The objects and other advantages of the present invention can be achieved and obtained by the structure specifically pointed out in the specification and the drawings.

[0030] Those skilled in the art will understand that the objects and advantages that can be achieved by the present invention are not limited to the above specifically described, and the above and other objects that the present invention can achieve will be more clearly understood according to the following detailed description. Description of the Drawings

[0031] The drawings described herein are used to provide a further understanding of the present invention, form a part of this application, and do not limit the present invention. In the drawings:

[0032] Figure 1 It is a schematic structural diagram of a room-temperature vacuum encapsulation device for an on-chip micro-system in an embodiment of the present invention.

[0033] Figure 2 It is an example of the position distribution of the cavity structure in an embodiment of the present invention.

[0034] Figure 3 It is a flowchart of an encapsulation method introducing an air injection step in an embodiment of the present invention.

[0035] Figure 4 Flow chart of wafer-level vacuum packaging method for on-chip microsystem in an embodiment of the present invention.

[0036] Figure 5 Schematic diagram of the moving trajectory of the laser focus along the bonding interface in an embodiment of the present invention.

[0037] Figure 6 Schematic diagram of multiple working components arranged on the microsystem substrate in an embodiment of the present invention.

[0038] Figure 7 Schematic diagram of the bonding trajectory in a rectangular grid pattern in an embodiment of the present invention.

[0039] Figure 8 Schematic diagram of the cavity structure for introducing getter in an embodiment of the present invention.

[0040] Figure 9 Flow chart of the vacuum packaging method for on-chip microsystem in an embodiment of the present invention.

[0041] Figure 10 Schematic diagram of the structure of the vacuum packaging equipment including a vacuum chamber in an embodiment of the present invention.

[0042] Figure 11 Schematic diagram of the structure of the room-temperature vacuum packaging equipment for on-chip microsystem in another embodiment of the present invention.

[0043] Figure 12 Schematic diagram of the structure of the vacuum packaging equipment including an air injection system in an embodiment of the present invention. Detailed implementation manners

[0044] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in combination with the embodiments and the accompanying drawings. Herein, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but not to limit the present invention.

[0045] Herein, it should also be noted that in order to avoid obscuring the present invention due to unnecessary details, only the structures and / or processing steps closely related to the solution of the present invention are shown in the drawings, while other details less related to the present invention are omitted.

[0046] It should be emphasized that the term "comprising / including" when used herein refers to the presence of features, elements, steps or components, but does not exclude the presence or addition of one or more other features, elements, steps or components.

[0047] Herein, it should also be noted that if not otherwise specified, the term "connection" in this article can not only refer to direct connection, but also represent indirect connection with an intermediate.

[0048] In the following, embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings, the same reference numerals represent the same or similar components, or the same or similar steps.

[0049] In recent years, the micro-system on a chip and the chip-level composite integration technology that integrate multiple modules such as MEMS microsystems, sensor devices, and CMOS integrated circuits on a single chip can significantly reduce the size, weight, power consumption, and cost of the integrated system, and are important integrated circuit and integrated system technologies. The existing vacuum packaging technology (or wafer bonding technology) for packaging the working components of the micro-system on a chip needs to be realized in a high-temperature environment. Since modules such as sensor devices and CMOS integrated circuits included in the micro-system on a chip are sensitive to temperature, the high-temperature environment is extremely likely to damage them. Therefore, the development of the wafer-level vacuum packaging technology for the micro-system on a chip under room temperature conditions is of great significance for the development of the system on chip (SoC) and the chip-level composite integration technology.

[0050] In order to overcome the problems existing in the above-mentioned prior art, such as the need for high-temperature conditions and the need to introduce an intermediate material layer at the bonding interface, the present invention proposes a method and device for vacuum packaging of a micro-system on a chip that can be carried out under room temperature environment.

[0051] Figure 1 It is a schematic structural diagram of the room temperature vacuum packaging device for the micro-system on a chip in an embodiment of the present invention. The system includes the following structures:

[0052] (1) An ultrafast laser generating device for generating ultrafast laser for bonding. Among them, the power, pulse repetition frequency, energy density, and focal position of the ultrafast pulsed laser are adjustable, and the pulse width of the ultrafast pulsed laser is in the femtosecond, picosecond, and nanosecond order of magnitude.

[0053] (2) A sealed chamber for accommodating the micro-system substrate and the cover substrate to be bonded. The sealed chamber includes a window for transmitting the ultrafast laser. Optionally, the sealed chamber can be a vacuum chamber. The window is located on the chamber wall of the vacuum chamber, and through this window, the laser can enter the vacuum chamber via this window. Optionally, the preset air pressure in the vacuum chamber is generally lower than 10 -3 Pa.

[0054] (3) A first displacement stage for supporting and moving the sealed chamber. Among them, the sealed chamber can be a vacuum chamber.

[0055] (4) The second displacement stage, located within the sealed chamber, is used to move the micro-system substrate and / or the cover substrate to be bonded. The position of the working components pre-processed on the micro-system substrate corresponds to the position of the concave cavity structure. It is also used to align, bond, and fix the bonding parts of the micro-system substrate and the cover substrate, so as to form a micro-chamber at the concave cavity structure, and make the working components of the on-chip micro-system located within the micro-chamber.

[0056] (5) The vacuum system, connected to the sealed chamber, is used to pump the vacuum degree of the sealed chamber to a preset air pressure after the micro-system substrate and the cover substrate are placed in the sealed chamber. The vacuum system includes a vacuum pump for obtaining a vacuum environment and a vacuum gauge for measuring the vacuum degree. It is used to pump the vacuum degree of the sealed chamber to a preset air pressure after the micro-system substrate and the cover substrate are placed in the sealed chamber; wherein, the micro-system substrate and / or the cover substrate has a concave cavity structure for accommodating the working components of the on-chip micro-system, and the micro-system substrate and / or the cover substrate can transmit the ultrafast laser for bonding at least at the bonding parts. Optionally, the bonding parts of the micro-system substrate and / or the cover substrate that can transmit the ultrafast laser are facing the window for transmitting the ultrafast laser. In the specific implementation process, the sealed chamber is connected to the vacuum system. In addition, the displacement stage in the sealed chamber also needs to be connected to the external cables (on the premise of ensuring tightness). The sealed chamber also has a chamber door that can be opened and closed to put in or take out the micro-system substrate and the cover substrate.

[0057] (6) The drive system is used to provide voltage drive for the ultrafast laser generating device, the first displacement stage, the second displacement stage, and the vacuum system.

[0058] In some embodiments of the present invention, the vacuum packaging device further includes: (7) The control system is used to control the working state of the ultrafast laser generating device, control the moving direction and speed of the first displacement stage and the second displacement stage, and control the working state of the vacuum system. The drive system is also used to provide voltage drive for the control system.

[0059] In the specific implementation process, the control system is used to control the power, pulse repetition frequency, energy density, and focal position of the ultrafast pulsed laser of the ultrafast laser generating device; control the moving direction and moving speed of at least one of the first displacement stage and the second displacement stage, control the first displacement stage to make the focal point of the ultrafast laser move along the bonding interface of the micro-system substrate and the cover substrate, and the moving trajectory covers all the bonding parts of the micro-system substrate and the cover substrate, control the second displacement stage to make the micro-system substrate and the cover substrate closely bond and fix at the bonding parts; control the opening and shutting of the vacuum pump and the vacuum gauge in the vacuum system.

[0060] In the specific implementation process, after the vacuum degree of the vacuum system reaches the preset value, the control system controls the first displacement stage and the second displacement stage to move along the preset path, and controls the ultrafast laser generating device to output an ultrafast laser beam according to the preset parameters, so as to automatically complete the bonding of the microsystem substrate and the cover substrate.

[0061] Among them, by controlling the first displacement stage and / or the second displacement stage, the ultrafast laser is focused at the bonding interface of the microsystem substrate and the cover substrate, and the focus of the ultrafast laser is moved along the bonding interface. The energy of the ultrafast laser is used to melt the materials of the microsystem substrate and the cover substrate near the focus, and after curing, the bonding of the microsystem substrate and the cover substrate near the focus is realized; by making the moving trajectory of the focus of the ultrafast laser surround the cavity structure at least once, the microchamber is closed, and the vacuum packaging of the on-chip microsystem is completed.

[0062] In the specific implementation process, the control system is further used to control the working states of the heating device and the gas injection system. It should be noted that controlling the working states of other systems or states by the control system belongs to the prior art.

[0063] By using the vacuum packaging equipment and method of the on-chip microsystem and the vacuum-packaged on-chip microsystem proposed by the present invention, the vacuum packaging of the on-chip microsystem under room temperature conditions can be realized, and no intermediate material layer is required, and direct bonding can be carried out, reducing the bonding process steps and costs, and greatly expanding the range of substrate materials applicable to vacuum packaging.

[0064] In some embodiments of the present invention, the microsystem substrate and / or the cover substrate have a cavity structure for accommodating the working components of the on-chip microsystem, so that after the microsystem substrate and the cover substrate are attached and fixed, a microchamber is formed at the cavity structure, and the working components of the on-chip microsystem are located in the microchamber; the microsystem substrate and / or the cover substrate can transmit the ultrafast laser for bonding at least at the bonding part; when the bonding parts of the microsystem substrate and the cover substrate are aligned, attached and fixed, a microchamber can be formed at the cavity structure, and the working components of the on-chip microsystem are located in the microchamber.

[0065] In some embodiments of the present invention, the ultrafast laser generated by the ultrafast laser generating device is used to be focused at the bonding interface of the microsystem substrate and the cover substrate, and the focus of the ultrafast laser is moved along the bonding interface. The energy of the ultrafast laser is used to melt the materials of the microsystem substrate and the cover substrate near the focus, and after curing, the bonding of the microsystem substrate and the cover substrate near the focus is realized.

[0066] Furthermore, in some embodiments of the present invention, the moving trajectory of the focus of the ultrafast laser surrounds the cavity structure at least once, so that the microchamber is closed, and the vacuum packaging of the on-chip microsystem is completed.

[0067] In the specific implementation process, the movement of the focus of the ultrafast laser can be achieved by moving the first displacement stage and / or the second displacement stage.

[0068] In some embodiments of the present invention, the vacuum packaging device further includes a heating device located above the second displacement stage. The heating device is used to heat the microsystem substrate and the cover substrate to be bonded to remove the gas molecules adsorbed on their surfaces, and the driving system is used to provide voltage drive for the heating device.

[0069] In some embodiments of the present invention, the vacuum packaging device further includes an air injection system. The air injection system is used to inject a specific type of atomic vapor into the vacuum chamber and stop injecting air when the concentration of the atomic vapor meets a preset condition, so that the microchamber formed at the concave cavity structure is filled with the preset type and concentration of atomic vapor after the bonding parts of the microsystem substrate and the cover substrate are aligned, attached and fixed. The driving system is used to provide voltage drive for the air injection system.

[0070] In some other embodiments, the working components of the on-chip microsystem can be not only solid structures processed on the microsystem substrate (such as mechanical moving components of MEMS, thermal sensitive components of micro thermal radiation imagers, electron emission components of micro vacuum electronic devices and systems, etc.), but also atomic vapor in atomic gas cells for fields such as quantum detection and quantum frequency standards, such as atoms of elements such as rubidium, cesium, potassium, sodium, calcium, and helium.

[0071] Correspondingly, after the vacuum degree of the sealed chamber is pumped to a preset air pressure and before the bonding parts of the microsystem substrate and the cover substrate are aligned, attached and fixed, the vacuum packaging method further includes: an air injection step of injecting a preset type of atomic vapor into the sealed chamber until the concentration of the atomic vapor meets a preset condition, so that the microchamber formed at the concave cavity structure is filled with the preset type and concentration of atomic vapor after the bonding parts of the microsystem substrate and the cover substrate are aligned, attached and fixed. And, before the bonding parts of the microsystem substrate and the cover substrate are aligned, attached and fixed, the vacuum packaging method further includes: a degassing step of heating the microsystem substrate and the cover substrate as a whole to a preset temperature and maintaining the heating for a preset duration to remove the gas adsorbed on the substrate surface.

[0072] Adopting this embodiment, the degassing step is beneficial to further remove the residual gas in the microchamber and further improve the vacuum degree of the sealed microchamber after bonding.

[0073] In some embodiments of the present invention, the vacuum packaging device further includes a leveling device. The leveling device is installed between the first displacement stage and the vacuum chamber and is used to adjust the microsystem substrate and the cover substrate to be in a horizontal state.

[0074] In some embodiments of the present invention, the material combinations on both sides of the bonding interface between the microsystem substrate and the cover substrate for bonding include: glass - silicon, glass - glass, quartz - silicon, quartz - quartz, glass - quartz, glass - metal, glass - ceramic, quartz - metal, and quartz - ceramic. The present invention is not limited to this, and the above are only examples. In the specific implementation process, the two substrates to be bonded only need to satisfy that at least one of them is transparent to the laser used for bonding. At least one of the microsystem substrate and the cover substrate can be entirely transparent to the laser used for bonding, or only transparent to the laser used for bonding at the bonding site. Optionally, the materials transparent to the laser include but are not limited to transparent ceramics, glass, quartz, sapphire, calcium fluoride (CaF 2 ) and magnesium fluoride (MgF 2 ), etc.

[0075] It can be seen that the vacuum packaging device proposed based on the present invention can greatly expand the range of substrate materials applicable to the vacuum packaging technology.

[0076] In some embodiments of the present invention, the microsystem substrate and the cover substrate are of wafer - level size and standard wafer shape. The present invention is not limited to this. The vacuum packaging device proposed by the present invention is applicable to the bonding of wafer - level microsystem substrates and cover substrates, and can also be used for the bonding of substrates with other shapes and sizes. For example, the microsystem substrate and / or the cover substrate can also be a substrate composed of multiple layers of materials, or a substrate containing through - holes and glass through - holes with penetrating micro - electrodes or a substrate with through - silicon vias. The characteristic points of the above substrates can be combined and split.

[0077] In some embodiments of the present invention, the microsystem substrate and / or the cover substrate is a substrate composed of multiple layers of materials; or, the microsystem substrate and the cover substrate are substrates containing through - holes and glass through - holes with penetrating micro - electrodes or through - silicon vias.

[0078] Among them, through - silicon via (TSV, Through Silicon Via) is an advanced semiconductor packaging and microelectronics technology, and through - glass via (TGV, Through - Glass Via) technology is a technology for manufacturing through - holes on a glass substrate.

[0079] It can be seen that the vacuum packaging device proposed by the present invention is applicable to microsystem substrates and cover substrates with various materials, sizes, shapes, and process characteristics.

[0080] In some embodiments of the present invention, when multiple working components are provided on the microsystem substrate to be bonded, and correspondingly multiple cavities are included on the cover substrate, the movement trajectory of the focus of the ultrafast laser should surround each cavity structure at least once, so as to obtain multiple on - chip microsystems that have completed vacuum packaging at one time.

[0081] In some embodiments of the present invention, when multiple working components are provided on the microsystem substrate to be bonded, correspondingly, multiple cavities are included on the cover substrate. The moving trajectory of the focus of the ultrafast laser should surround each cavity structure at least once, so as to obtain multiple on-chip microsystems that have completed vacuum packaging at one time. In order to achieve airtight isolation between the micro-vacuum chamber accommodating the working components of the microsystem substrate and the external environment, the moving trajectory of the laser focus relative to the microsystem substrate and the cover substrate needs to surround the cavity structure at least once to ensure that the micro-vacuum chambers formed by the cavity structures are all surrounded by at least one bonding trajectory. Further, the moving trajectory of the focus of the ultrafast laser needs to surround each cavity structure at least once and the trajectory is closed.

[0082] Correspondingly, after obtaining multiple on-chip microsystems that have completed vacuum packaging at one time, the vacuum packaging method further includes: a dicing step, dicing the bonded microsystem substrate and cover substrate to obtain each independent on-chip microsystem that has completed vacuum packaging.

[0083] In the specific implementation process, if the microsystem substrate and the cover substrate are wafer-level, then what is obtained after bonding is an entire bonded wafer, and each on-chip microsystem on the wafer is a die, and each independent die can be obtained by dicing.

[0084] By adopting this embodiment, multiple on-chip microsystems that have completed vacuum packaging can be obtained at one time, and at the wafer-level scale, multiple dice can be obtained at one time.

[0085] Corresponding to the above-mentioned vacuum packaging device for on-chip microsystems, the present invention also proposes a vacuum packaging method for on-chip microsystems. Figure 9 It is a flowchart of the vacuum packaging method for on-chip microsystems in an embodiment of the present invention. The method includes the following steps:

[0086] Step S110: Place the microsystem substrate and the cover substrate in a sealed chamber, and evacuate the vacuum degree of the sealed chamber to a preset air pressure; wherein, the microsystem substrate and / or the cover substrate has a cavity structure for accommodating the working components of the on-chip microsystem, and the microsystem substrate and / or the cover substrate can transmit the ultrafast laser for bonding at least at the bonding part.

[0087] In the specific implementation process, before or after evacuating the vacuum degree of the closed and independent chamber to the preset air pressure, align the bonding parts of the microsystem substrate and the cover substrate but do not contact them. The preset air pressure condition can be expressed by physical quantities such as vacuum degree, atmospheric density, specific gas density or air pressure value. When the sealed chamber is evacuated to a vacuum, when the two substrates are aligned and closely attached in the vacuum environment, a closed and airtight micro-vacuum chamber is formed at the cavity structure.

[0088] For the position of the cavity structure, Figure 2 This is an example of the position distribution of the cavity structure in an embodiment of the present invention. In Example 1, the cavity structure is located on the cover substrate; in Example 2, the cavity structure is located on the microsystem substrate; in Example 3, the cavity structure is located on both the cover substrate and the microsystem substrate. In the specific implementation process, the cavity structure can be obtained by etching a planar substrate, or a closed fence can be deposited or bonded on the planar substrate.

[0089] Step S120: The position of the working component pre-processed on the microsystem substrate corresponds to the position of the cavity structure. Align, attach, and fix the bonding parts of the microsystem substrate and the cover substrate so that a microchamber is formed at the cavity structure, and the working components of the on-chip microsystem are located in the microchamber. Before encapsulation, the working components of the on-chip microsystem are generally processed on the microsystem substrate, and the working components and the microsystem substrate can be regarded as a whole.

[0090] In the specific implementation process, in order to achieve tight fitting and fixation of the microsystem substrate and the cover substrate at all bonding parts, the microsystem substrate and the cover substrate are placed absolutely parallel, and the substrates are smooth and flat at the bonding parts. After fitting, a certain pressure is applied and maintained.

[0091] Step S130: Focus the ultrafast laser on the bonding interface of the microsystem substrate and the cover substrate, control the focus of the ultrafast laser to move along the bonding interface, and use the energy of the ultrafast laser to melt the materials of the microsystem substrate and the cover substrate near the focus. After solidification, bonding of the microsystem substrate and the cover substrate near the focus is achieved. Among them, the difference between the two concepts of the bonding part and the bonding interface is that the bonding part refers to the local part on the substrate that is pre-designed for attachment and bonding before the two substrates are attached, and the bonding interface is a conceptually formed interface after the two substrates are attached.

[0092] Step S140: By making the movement trajectory of the focus of the ultrafast laser surround the cavity structure at least once, the microchamber is sealed, and the vacuum encapsulation of the on-chip microsystem is completed. Among them, the ultrafast laser can be a femtosecond ultrafast laser or a picosecond ultrafast laser.

[0093] In the specific implementation process, in order to achieve the bonding effect, it is necessary to set the power, pulse repetition frequency, and energy density of the ultrafast laser to preset values before bonding. The set power, pulse repetition frequency, and energy density of the ultrafast laser need to vary according to the material of the substrate to be bonded. The higher the melting point of the substrate material to be bonded, the greater the power of the required ultrafast laser. The ultrafast laser (femtosecond or picosecond ultrafast laser) can cause local instantaneous melting of the micro-system substrate and the cover substrate materials, and realize the bonding of the two substrates near the focus after rapid solidification. When the moving trajectory of the focus of the ultrafast laser covers all the areas to be bonded, the bonding of the entire micro-system substrate and the cover substrate can be achieved. Since at each moment, the range of local instantaneous melting and bonding of the micro-system substrate and the cover substrate materials is only limited to a range of about micron magnitude near the focus, and the power of the ultrafast laser is limited, the temperature rise of the micro-system substrate and the cover substrate during the entire bonding process can be ignored and is basically at room temperature. Therefore, high temperature will not affect the performance of the working components.

[0094] The advantages of the on-chip micro-system vacuum packaging method proposed by the present invention are that it can realize the vacuum packaging of the on-chip micro-system under room temperature conditions, without an intermediate material layer, can be directly bonded, reduces the bonding process steps and costs, and greatly expands the range of substrate materials applicable to vacuum packaging.

[0095] In some embodiments of the present invention, before placing the micro-system substrate and the cover substrate in a sealed chamber, the method further includes: introducing a getter on the inner wall of the cavity structure on the micro-system substrate and / or the cover substrate. Wherein, the material of the getter is composed of one or more of the following metals: titanium, zirconium, vanadium, iron, barium, and aluminum. Correspondingly, after the bonding of the micro-system substrate and the cover substrate is completed, the method further includes: heating the bonded substrates as a whole or locally heating the position where the getter is introduced to activate the getter, so that the getter adsorbs the residual gas in the micro-cavity formed at the cavity structure.

[0096] Adopting this embodiment, the introduction and activation of the getter are beneficial to further remove the residual gas in the micro-cavity and further improve the vacuum degree of the sealed micro-cavity after bonding.

[0097] On the basis of the above embodiments, further, before aligning, attaching, and fixing the bonding parts of the micro-system substrate and the cover substrate, the method further includes: a degassing step, by heating the micro-system substrate and the cover substrate to a preset temperature as a whole and maintaining the heating for a preset duration to remove the gas adsorbed on the substrate surface.

[0098] Adopting this embodiment, the degassing step is beneficial to further remove the residual gas in the micro-cavity and further improve the vacuum degree of the sealed micro-cavity after bonding.

[0099] In some embodiments of the present invention, the working components of the on-chip microsystem can be not only solid structures processed on the microsystem substrate (such as the mechanical moving components of MEMS, the heat-sensitive components of micro thermal radiation imagers, the electron emission components of micro-vacuum electronic devices and systems, etc.), but also atomic vapors in atomic gas cells for fields such as quantum detection and quantum frequency standards, such as atomic vapors of elements such as rubidium, cesium, potassium, sodium, calcium, and helium.

[0100] Correspondingly, after pumping the vacuum degree of the closed chamber to a preset air pressure, before aligning, attaching, and fixing the bonding parts of the microsystem substrate and the cover substrate, the method further includes an air injection step of injecting a preset type of atomic vapor into the closed chamber until the concentration of the atomic vapor meets a preset condition, so that the microchamber formed at the concave cavity structure is filled with the preset type and concentration of atomic vapor after aligning, attaching, and fixing the bonding parts of the microsystem substrate and the cover substrate.

[0101] In the specific implementation process, as Figure 3 shown ( Figure 3 which is a flowchart of the packaging method introducing the air injection step in an embodiment of the present invention), injecting atomic vapor of a specific type and specific air pressure into the vacuum chamber, so that the atomic vapor of the specific type and air pressure is dispersed in the concave cavity structures of the microsystem substrate and the cover substrate. In this way, after bonding, the micro-vacuum chamber formed by the concave cavity structure is filled with atomic vapor of a specific type and air pressure.

[0102] Adopting this embodiment, it is possible to fill the microchamber with the preset type and concentration of atomic vapor through the air injection step, which is beneficial to realizing the preparation of MEMS atomic gas cells at room temperature. Therefore, the present invention further provides a method for wafer-level preparation of MEMS atomic gas cells at room temperature. Compared with the existing processing methods of MEMS atomic gas cells that all need to be carried out at high temperature, resulting in problems such as low air pressure and atomic concentration in the atomic gas cell and being difficult to control, this method can be carried out at room temperature, and the air pressure and atomic concentration of the atomic gas cell can be accurately controlled by controlling the air pressure of the vacuum chamber.

[0103] In some embodiments of the present invention, during the process of controlling the focus of the ultrafast laser to move along the bonding interface, the method further includes using a leveling device to adjust the microsystem substrate and the cover substrate to be in a horizontal state.

[0104] Adopting this embodiment is beneficial to ensuring that the laser focus and the bonding point do not deviate from the bonding interface of the microsystem substrate and the cover substrate during the bonding process, and ensuring the airtightness of the final bonded product.

[0105] Optionally, the material combinations on both sides of the bonding interface of the microsystem substrate and the cover plate substrate for bonding include: glass-silicon, glass-glass, quartz-silicon, quartz-quartz, glass-quartz, glass-metal, glass-ceramic, quartz-metal, and quartz-ceramic. The present invention is not limited thereto, and the above are only examples. In the specific implementation process, the two substrates to be bonded only need to satisfy that at least one of them can be transparent to the laser. At least one of the microsystem substrate and the cover plate substrate can be entirely transparent to the laser used for bonding, or only transparent to the laser used for bonding at the bonding site. Optionally, the materials transparent to the laser include, but are not limited to, transparent ceramics, glass, quartz, sapphire, calcium fluoride (CaF 2 ) and magnesium fluoride (MgF 2 ), etc.

[0106] It can be seen from this that the method proposed by the present invention can greatly expand the range of substrate materials applicable to the vacuum packaging technology.

[0107] In the specific implementation process, the microsystem substrate and the cover plate substrate can be of wafer-level size and standard wafer shape. The present invention is not limited thereto. The method proposed by the present invention is applicable to the bonding of wafer-level microsystem substrates and cover plate substrates, and can also be used for the bonding of substrates of other shapes and sizes. For example, the microsystem substrate and / or the cover plate substrate can also be a substrate composed of multiple layers of materials, or a substrate containing through-holes and glass through-holes or silicon through-holes penetrating microelectrodes. The characteristic points of the above substrates can be combined and split.

[0108] Among them, through-silicon via (TSV) is an advanced semiconductor packaging and microelectronics technology, and through-glass via (TGV) technology is a technology for manufacturing through-holes on a glass substrate.

[0109] It can be seen that the method proposed by the present invention is applicable to microsystem substrates and cover plate substrates with various materials, sizes, shapes, and process characteristics.

[0110] In some embodiments of the present invention, when multiple working components are provided on the microsystem substrate to be bonded, and correspondingly multiple cavities are included on the cover plate substrate, the movement trajectory of the focus of the ultrafast laser should surround each cavity structure at least once, so as to obtain multiple on-chip microsystems that have completed vacuum packaging at one time. In order to hermetically isolate the micro-vacuum chamber accommodating the working components of the microsystem substrate from the external environment, the movement trajectory of the laser focus relative to the microsystem substrate and the cover plate substrate needs to surround the cavity structure at least once to ensure that the micro-vacuum chambers formed by the cavity structures are all surrounded by at least one bonding trajectory. Further, the movement trajectory of the focus of the ultrafast laser needs to surround each cavity structure at least once and the trajectory is closed.

[0111] Correspondingly, after obtaining multiple completed vacuum-packaged on-chip microsystems at one time, the method further includes: a dicing step of dicing the bonded microsystem substrate and the cover substrate to obtain each independent completed vacuum-packaged on-chip microsystem.

[0112] In the specific implementation process, if the microsystem substrate and the cover substrate are wafer-level, then what is obtained after bonding is an entire bonded wafer, and each on-chip microsystem on the wafer is a die, and each independent die can be obtained by dicing.

[0113] By adopting this implementation manner, multiple completed vacuum-packaged on-chip microsystems can be obtained at one time, and at the wafer-level scale, multiple dice can be obtained at one time.

[0114] Figure 4 This is a flowchart of the wafer-level vacuum packaging method for an on-chip microsystem in an embodiment of the present invention. In this specific embodiment, the sealed chamber is a vacuum chamber, the micro chamber is a micro-closed vacuum chamber, and the substrate to be packaged is in the shape and size of a wafer-level. The method includes the following steps:

[0115] Step 1: Preparation step, prepare the microsystem substrate 1 to be bonded and the cover substrate 3, wherein the cover substrate has a cavity structure 4, so that the working component 2 of the on-chip microsystem can be accommodated in the micro-closed vacuum chamber 41 formed by the cavity structure 4 after bonding. Wherein, at least one of the microsystem substrate and the cover substrate is transparent to the laser 7 for bonding at the bonding site 5, so that the laser can pass through the microsystem substrate or the cover substrate to reach the bonding site.

[0116] Step 2: Vacuum pumping step, place the microsystem substrate and the cover substrate in the vacuum chamber 6, so that the two substrates are placed parallel to each other, and their bonding sites are aligned but not in contact, and pump the vacuum degree of the vacuum chamber to a preset air pressure. Wherein, the microsystem substrate and the cover substrate can be adjusted to be in a horizontal state by a leveling device.

[0117] In the specific implementation process, align the bonding sites of the microsystem substrate and the cover substrate, so that the cavity structure 4 forms a closed micro-vacuum chamber 41 after bonding to accommodate the working component 2 of the microsystem. The working component can be a mechanical moving component of a micro-electromechanical system (MEMS), a heat-sensitive component of a micro-thermal radiation imager, an electron emission component of a micro-vacuum electronic device and system, an atomic vapor of an atomic gas chamber, etc.

[0118] Step 3: Bonding step. Control the movement of the microsystem substrate and / or the cover substrate so that the microsystem substrate and the cover substrate are closely bonded and fixed at the bonding sites. To achieve the close bonding and fixing of the microsystem substrate and the cover substrate at all bonding sites, the microsystem substrate and the cover substrate need to be placed absolutely parallel, and the bonding sites need to be smooth and flat. After bonding, a certain pressure needs to be applied and maintained.

[0119] Step 4: Bonding step. Focus an ultrafast laser with a pulse width in the femtosecond or picosecond range on the bonding interface of the microsystem substrate and the cover substrate or near it, so that the microsystem substrate and the cover substrate are locally melted and bonded at the bonding interface. At the same time, control one or more of the microsystem substrate, the cover substrate, and the laser beam to move along a preset path, so that the laser focus 71 moves along the bonding interface of the microsystem substrate and the cover substrate, and the movement trajectory covers all the bonding sites of the microsystem substrate and the cover substrate.

[0120] Figure 5 It is a schematic diagram of the movement trajectory of the laser focus along the bonding interface in an embodiment of the present invention. The movement trajectory 8 of the laser focus around the cavity structure can be multiple nested closed rectangles or multiple concentric circles. There is no specific limitation on this, as long as the trajectory is closed and encloses each cavity structure.

[0121] Step 5: Ending step. Increase the air pressure in the vacuum chamber to be greater than or equal to the atmospheric pressure, and open the vacuum chamber to take out the wafer that has completed bonding from the vacuum chamber.

[0122] When there are multiple working components on the microsystem substrate to be bonded, and there are multiple cavities on the cover substrate, a wafer containing multiple microsystems is obtained at one time after bonding, as Figure 6 shown, Figure 6 It is a schematic diagram of setting multiple working components on the microsystem substrate in an embodiment of the present invention. To obtain a single microsystem device, it further includes Step 6: Dicing step. Dice the bonded wafer to obtain die. This Step 6 can be carried out before or after the ending step of Step 5. For example, if dicing is performed using the ultrafast laser for bonding, the dicing step can be completed before the ending step.

[0123] Correspondingly, for the case where there are multiple microsystems after substrate bonding, in order to hermetically isolate each micro-vacuum chamber containing the working components of the microsystem substrate from the external environment, the movement trajectory of the laser focus relative to the microsystem substrate and the cover substrate needs to surround each cavity structure at least once, to ensure that each micro-vacuum chamber formed by the cavity structure is surrounded by at least one circle of bonding trajectory.

[0124] Figure 7Schematic diagram of the bonding trajectory in a rectangular grid pattern in an embodiment of the present invention. In order to reduce the distance of the movement trajectory of the laser focus during the bonding of the entire wafer to improve the bonding efficiency, the wafer bonding including multiple microsystem arrays can adopt Figure 7 the bonding trajectory in the rectangular grid pattern shown, as Figure 7 shown. Adopting this bonding trajectory can greatly reduce the moving distance of the laser focus relative to the microsystem substrate and the cover substrate during bonding, so that the bonding time required for a wafer with N microsystem arrays is much less than N times the bonding time required for a single microsystem.

[0125] Based on the specific embodiment shown in Figure 4 in order to improve the vacuum degree of the enclosed micro-vacuum chamber, in some embodiments of the present invention, after the evacuation step and before the bonding step, a degassing step is further included, heating the microsystem substrate and the cover substrate to a preset temperature and for a preset time to remove the adsorbed gas on their surfaces.

[0126] Based on the specific embodiment shown in Figure 4 in order to further improve the vacuum degree of the enclosed micro-vacuum chamber, in some embodiments of the present invention, the preparation step further includes preparing a layer of getter 9 on the surface of the concave cavity structure (as Figure 8 shown, Figure 8 schematic diagram of the concave cavity structure with a getter introduced in an embodiment of the present invention). And after the bonding step or the end step, an activation step is further included, by heating the bonded wafer as a whole or locally heating the getter to activate the getter, so that the getter adsorbs the residual gas in the concave cavity structure, thereby improving the vacuum degree of the micro-vacuum chamber. Among them, the material of the getter can be composed of one or more of the following metals: titanium, zirconium, vanadium, iron, barium and aluminum.

[0127] Figure 10 Schematic diagram of the structure of a vacuum packaging device including a vacuum chamber in an embodiment of the present invention. The vacuum chamber is fixed on the first displacement stage and is used to provide a vacuum environment for vacuum packaging. The vacuum chamber includes a window 61 that can transmit ultrafast laser on the chamber wall of the vacuum chamber, so that the ultrafast laser can enter the interior of the vacuum chamber through the window; a second displacement stage 9 inside the vacuum chamber to support and move the microsystem substrate and / or the cover substrate to be bonded, so that the microsystem substrate and the cover substrate are closely attached.

[0128] As Figure 10As shown, in some embodiments of the present invention, one of the microsystem substrate and the cover substrate to be bonded is fixed to one side of the window that can transmit ultrafast laser in the vacuum chamber and is closely attached to the window. In this way, the window on the chamber wall of the vacuum chamber can be used to support the microsystem substrate or the cover substrate to be bonded, without an additional support platform, thus simplifying the device structure and reducing the device cost. On the other hand, there is no gap between the window on the chamber wall of the vacuum chamber and the microsystem substrate or the cover substrate to be bonded, thereby reducing the number of reflection interfaces on the laser transmission path and the energy loss during the laser transmission process, and at the same time making it easier to achieve and accurately control the laser focusing on the bonding interface of the microsystem substrate and the cover substrate.

[0129] In some embodiments of the present invention, as Figure 10 shown, the vacuum packaging device further includes a heating device 10 located above the second displacement stage 9. The heating device is used to heat the microsystem substrate and the cover substrate to be bonded to remove the gas molecules adsorbed on their surfaces, control the working state of the heating device by using the control system, and provide voltage drive for the heating device by using the drive system.

[0130] Adopting this implementation manner, the vacuum degree of the micro closed chamber obtained after packaging can be improved by introducing a heating device.

[0131] In some embodiments of the present invention, the vacuum packaging device further includes an air injection system, as Figure 8 shown, the air injection system is used to inject atomic vapor of a specific type into the vacuum chamber and stop injecting air when the concentration of the atomic vapor meets a preset condition, control the working state of the air injection system by using the control system, and provide voltage drive for the air injection system by using the drive system.

[0132] In some embodiments of the present invention, the vacuum packaging device further includes a leveling device. The leveling device is installed between the first displacement stage and the vacuum chamber and is used to adjust the microsystem substrate and the cover substrate to be in a horizontal state.

[0133] Adopting this implementation manner, by introducing a leveling device, it is beneficial that when controlling the movement of the first displacement stage relative to the microsystem substrate and the cover substrate to the focus and bonding point of the ultrafast laser, the laser focus and the bonding point will not deviate from the bonding interface of the microsystem substrate and the cover substrate.

[0134] Corresponding to the above vacuum packaging device and method, the present invention further provides a vacuum-packaged on-chip microsystem. The on-chip microsystem realizes vacuum packaging based on the vacuum packaging method of the on-chip microsystem in any one of the above implementation manners.

[0135] Figure 11 It is a schematic structural diagram of a wafer-level room-temperature vacuum packaging device for an on-chip microsystem in another embodiment of the present invention. InFigure 1 An air injection system is added on the basis of [description of previous basis], and it shows controlling the working state of the air injection system by using the said control system, and providing voltage drive for the air injection system by using the said drive system.

[0136] Figure 12 It is a schematic structural diagram of a vacuum packaging device including an air injection system in an embodiment of the present invention. In some embodiments of the present invention, the vacuum packaging device further includes an air injection system for injecting atomic vapor of a specific type and specific pressure into the vacuum chamber. The air injection system includes a gas source, a barometer, and a gas valve. Therefore, this device can also be used for wafer-level processing of MEMS atomic gas cells at room temperature.

[0137] As above, the vacuum packaging device proposed by the present invention can realize the vacuum packaging method of the on-chip microsystem proposed in the above embodiments.

[0138] In summary, the advantages of the vacuum packaging device and method of the on-chip microsystem proposed by the present invention are as follows: (1) It can realize the vacuum packaging of the on-chip microsystem under room temperature conditions. This packaging technology can be applied to wafer-level vacuum packaging, which is beneficial to solving the problem that the previous wafer-level vacuum packaging technology requires high temperature; (2) There is no need for an intermediate material layer. The microsystem substrate and the cover substrate can be directly bonded, reducing the bonding process steps and costs, which is beneficial to solving the problems of complex process and high cost caused by the need for an intermediate material layer in some previous bonding technologies; (3) The ultrafast laser can instantaneously melt almost all materials, even refractory materials. It can realize the direct bonding between almost all material substrates, as long as at least one of the two substrates to be bonded is transparent to the laser, which is beneficial to solving the problem that only a small number of material substrates can be directly bonded in the previous technology, and greatly expands the range of substrate materials applicable to vacuum packaging.

[0139] Those of ordinary skill in the art should understand that the various exemplary components, systems, and methods described in combination with the embodiments disclosed herein can be implemented in hardware, software, or a combination of both. Specifically, whether to implement it in hardware or software depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention. When implemented in hardware, it can be, for example, an electronic circuit, an application-specific integrated circuit (ASIC), appropriate firmware, a plug-in, a functional card, etc. When implemented in software, the elements of the present invention are programs or code segments used to execute the required tasks. The program or code segment can be stored in a machine-readable medium, or transmitted through a data signal carried in a carrier wave on a transmission medium or a communication link.

[0140] It should be clear that the present invention is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications, and additions, or change the order between steps after understanding the spirit of the present invention.

[0141] In the present invention, features described and / or illustrated for one embodiment can be used in the same or a similar manner in one or more other embodiments, and / or combined with the features of other embodiments or replace the features of other embodiments.

[0142] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, various changes and modifications can be made to the embodiments of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A vacuum packaging device for a microsystem on a chip, characterized in that: The vacuum packaging equipment comprises: An ultrafast laser generating device, used for generating ultrafast laser for bonding; A sealed chamber, used to accommodate the microsystem substrate and the cover substrate to be bonded, the sealed chamber comprising a window for transmitting the ultrafast laser; A first translation stage, used for supporting and moving the sealed chamber; A second translation stage is located in the sealed chamber and is used to move the microsystem substrate and / or the cover substrate to be bonded. The position of the working part pre-processed on the microsystem substrate corresponds to the position of the cavity structure. The second translation stage is also used to align, attach and fix the bonding parts of the microsystem substrate and the cover substrate. A vacuum system connected to the sealed chamber, used to evacuate the vacuum degree of the sealed chamber to a preset pressure after the microsystem substrate and the cover substrate are placed in the sealed chamber; The driving system is used to provide voltage driving to the ultrafast laser generating device, the first translation stage, the second translation stage and the vacuum system.

2. The vacuum packaging equipment according to claim 1, characterized in that: The microsystem substrate and / or the cover substrate has a concave cavity structure for accommodating working components of the on-chip microsystem, so that after the microsystem substrate and the cover substrate are attached and fixed, a micro chamber is formed at the concave cavity structure, and the working components of the on-chip microsystem are located in the micro chamber; the microsystem substrate and / or the cover substrate can transmit the ultrafast laser used for bonding at least at the bonding position; When the bonding parts of the microsystem substrate and the cover substrate are aligned, attached and fixed, a micro chamber can be formed at the concave cavity structure, so that the working parts of the on-chip microsystem are located in the micro chamber.

3. The vacuum packaging equipment according to claim 2, characterized in that: The ultrafast laser generated by the ultrafast laser generating device is used to focus on the bonding interface between the microsystem substrate and the cover substrate. The focus of the ultrafast laser moves along the bonding interface. The energy of the ultrafast laser is used to melt the materials of the microsystem substrate and the cover substrate near the focus. After solidification, the bonding of the microsystem substrate and the cover substrate near the focus is achieved.

4. The vacuum packaging equipment according to claim 2, characterized in that: The moving track of the focus of the ultrafast laser circles the concave cavity structure for at least one cycle, so that the micro chamber is closed and the vacuum packaging of the on-chip microsystem is completed.

5. The vacuum packaging equipment according to claim 1, characterized in that: The vacuum packaging equipment also includes a heating device located on the second displacement stage, which is used to heat the microsystem substrate and the cover substrate to be bonded to remove gas molecules adsorbed on their surfaces, and the driving system is used to provide voltage drive to the heating device.

6. The vacuum packaging equipment according to claim 1, characterized in that: The vacuum packaging equipment also includes a gas injection system, which is used to inject a specific type of atomic vapor into the vacuum chamber and stop injecting gas when the concentration of the atomic vapor meets a preset condition, so that after the bonding parts of the microsystem substrate and the cover substrate are aligned, attached and fixed, the micro chamber formed at the concave cavity structure is filled with atomic vapor of preset type and concentration, and the driving system is used to provide voltage drive to the gas injection system.

7. The vacuum packaging equipment according to claim 1, characterized in that: The vacuum packaging equipment further comprises a leveling device, which is installed between the first displacement stage and the vacuum chamber and is used to adjust the microsystem substrate and the cover substrate to be in a horizontal state.

8. The vacuum packaging equipment according to claim 1, characterized in that: The vacuum packaging equipment also includes a control system for controlling the working state of the ultrafast laser generating device, for controlling the moving direction and speed of the first translation stage and the second translation stage, and for controlling the working state of the vacuum system.

9. The vacuum packaging equipment according to claim 1, characterized in that: The material combinations on both sides of the bonding interface of the bonded microsystem substrate and the cover substrate include: glass-silicon, glass-glass, quartz-silicon, quartz-quartz, glass-quartz, glass-metal, glass-ceramic, quartz-metal and quartz-ceramic.

10. The vacuum packaging equipment according to claim 1, characterized in that: The microsystem substrate and the cover substrate are of wafer-level size and standard wafer shape.

11. The vacuum packaging equipment according to claim 1, characterized in that: The microsystem substrate and / or cover substrate is a substrate composed of multilayer materials; or, the microsystem substrate and cover substrate are substrates containing through holes and glass through holes penetrating microelectrodes or substrates containing silicon through holes.

12. The vacuum packaging equipment according to claim 1, characterized in that: When a plurality of working parts are arranged on the microsystem substrate to be bonded, and a plurality of concave cavities are included on the cover substrate accordingly, the moving trajectory of the focus of the ultrafast laser should circle each concave cavity structure at least once, so as to obtain a plurality of vacuum-packaged on-chip microsystems at one time.

13. A vacuum-encapsulated microsystem on chip, characterized in that: The micro-system on chip is vacuum packaged based on the vacuum packaging equipment of the micro-system on chip according to any one of claims 1-12.

14. A vacuum packaging method for a microsystem on a chip, characterized in that: include: Placing the microsystem substrate and the cover substrate in a sealed chamber, and pumping the vacuum of the sealed chamber to a preset pressure; wherein the microsystem substrate and / or the cover substrate have a concave cavity structure for accommodating working components of the on-chip microsystem, and the microsystem substrate and / or the cover substrate can transmit the ultrafast laser used for bonding at least at the bonding position; The position of the working component pre-processed on the microsystem substrate corresponds to the position of the cavity structure, and the bonding parts of the microsystem substrate and the cover substrate are aligned, attached and fixed to form a micro chamber at the cavity structure, so that the working component of the on-chip microsystem is located in the micro chamber; Focusing the ultrafast laser on the bonding interface between the microsystem substrate and the cover substrate, controlling the focus of the ultrafast laser to move along the bonding interface, using the energy of the ultrafast laser to melt the materials of the microsystem substrate and the cover substrate near the focus, and achieving bonding of the microsystem substrate and the cover substrate near the focus after solidification; By making the moving trajectory of the focus of the ultrafast laser circle the concave cavity structure for at least one circle, the micro chamber is closed and the vacuum packaging of the on-chip microsystem is completed.

15. The method according to claim 14, characterized in that Before placing the microsystem substrate and the cover substrate in the sealed chamber, the method further comprises: introducing a getter into the inner wall of the concave cavity structure on the microsystem substrate and / or the cover substrate; After the bonding of the microsystem substrate and the cover substrate is completed, the method further includes: heating the bonded substrate as a whole or locally heating the location where the getter is introduced to activate the getter so that the getter absorbs residual gas in the micro chamber formed at the concave cavity structure.

16. The method according to any one of claims 14-15, characterized in that Before aligning, attaching and fixing the bonding parts of the microsystem substrate and the cover substrate, the method also includes: a degassing step, by heating the microsystem substrate and the cover substrate as a whole to a preset temperature and maintaining the heating for a preset time to remove the gas adsorbed on the surface of the substrate.

17. The method according to claims 14-16, characterized in that After the vacuum degree of the sealed chamber is evacuated to a preset pressure, and before the bonding parts of the microsystem substrate and the cover substrate are aligned, attached and fixed, the method further includes: Atomic vapor of a preset type is injected into the closed chamber until the concentration of the atomic vapor meets a preset condition, so that the micro chamber formed at the concave cavity structure is filled with atomic vapor of the preset type and concentration after the bonding parts of the microsystem substrate and the cover substrate are aligned, attached and fixed.

18. The method according to claim 14, characterized in that In the process of controlling the focus of the ultrafast laser to move along the bonding interface, the method further comprises: using a leveling device to adjust the microsystem substrate and the cover substrate to a horizontal state.

19. The method according to claim 14, characterized in that When a plurality of working parts are arranged on the microsystem substrate to be bonded, and a plurality of concave cavities are included on the cover substrate accordingly, the moving trajectory of the focus of the ultrafast laser should circle each concave cavity structure at least once, so as to obtain a plurality of vacuum-packaged on-chip microsystems at one time.

20. The method according to claim 19, characterized in that After obtaining a plurality of vacuum-packaged on-chip microsystems at one time, the method further comprises: The dicing step is to obtain each independent vacuum-packaged on-chip microsystem by dicing the bonded microsystem substrate and cover substrate.

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