Molecular clock waveguide, manufacturing method thereof and molecular clock

Abstract

The invention provides a molecular clock waveguide, a manufacturing method thereof and a molecular clock, relates to the field of molecular clocks, and can realize miniaturization of the molecular clock and long-term stability of air tightness. The molecular clock waveguide includes a first substrate, a first cover plate, and an airbag package. The surface of the first substrate is provided with a main groove and an auxiliary groove. The first cover plate covers the main groove and the auxiliary groove to form a main air chamber and an auxiliary air chamber respectively, and the main air chamber is communicated with the auxiliary air chamber. The air bag package is arranged in the auxiliary air chamber, the air bag package is provided with a first cavity, a shell of the air bag package is provided with a notch, and the first cavity is communicated with the auxiliary air chamber through the notch.

Description

Technical Field

[0001] The present application relates to the field of molecular clocks, and in particular to a molecular clock waveguide and a manufacturing method thereof, and a molecular clock. Background Art

[0002] With the emergence of communication rates and ultra-large networks, increasingly higher requirements are being placed on time synchronization and holdover time of devices, which in turn requires long-term frequency stability of clocks.

[0003] Molecular clock technology can provide high-frequency stability at the level of quantum resonance. Molecular clocks utilize a high-frequency signal to stimulate energy level transitions in the electrons of a specific gas, generating a frequency source with high long-term stability. These specific gas molecules must be stored in a waveguide, where the gas pressure must be relatively low and stable over the long term.

[0004] Existing molecular clock waveguides use traditional metal machining methods to create a metal cavity, a metal waveguide within the cavity, and a rarefied gas. After the rarefied gas is injected into the cavity, the cavity is sealed by mechanical pinching. This results in poor long-term airtightness and stability. Furthermore, molecular clocks are bulky, difficult to mass-produce, and expensive. Summary of the Invention

[0005] The present application provides a molecular clock waveguide and a method for manufacturing the same, as well as a molecular clock, which can achieve miniaturization of the molecular clock and long-term stability of its airtightness.

[0006] The present application provides a molecular clock waveguide comprising a first substrate, a first cover plate, and an airbag package. The first substrate has a surface provided with a primary groove and a secondary groove. The first cover plate covers the primary groove and the secondary groove to form a primary air chamber and a secondary air chamber, respectively, with the primary air chamber and the secondary air chamber communicating with each other. The airbag package is disposed within the secondary air chamber and has a first cavity. A notch is provided in the housing of the airbag package, communicating the first cavity with the secondary air chamber via the notch.

[0007] The molecular clock waveguide provided by the present application can be processed and manufactured using MEMS (micro-electro-mechanical system) technology, thereby achieving miniaturization, high integration, batch manufacturing, etc. of the molecular clock, and reducing production costs. In addition, wafer-level packaging can be performed based on MEMS technology, which can well meet the airtightness requirements of the molecular clock waveguide and ensure the long-term stability of the airtightness in the cavity. On this basis, the molecular clock waveguide provided by the present application, by additionally providing a secondary air chamber connected to the main air chamber, and providing an airbag package in the secondary air chamber, after completing the waveguide packaging, the gas in the shell of the airbag package is destroyed from the outside and released into the secondary air chamber and the main air chamber. In this way, the original control of the gas pressure in the main air chamber can be converted into control of the volume (main air chamber, secondary air chamber, first cavity), while ensuring the long-term stability of the airtightness, the difficulty of controlling the gas pressure is greatly reduced.

[0008] In some possible implementations, the airbag package includes a second substrate and a second cover plate, wherein a first groove is provided on a surface of the second substrate, and the second cover plate covers the first groove to form a first cavity.

[0009] In some possible implementations, the airbag package includes: a sealed glass bulb having a first cavity.

[0010] In some possible implementations, the first substrate has a partition wall between the main groove and the sub-groove, a gap is formed between the partition wall and the first cover plate, and the main air chamber and the sub-air chamber are connected through the gap.

[0011] In some possible implementations, the molecular clock waveguide further includes a metal layer, which covers the inner wall of the main groove and may also cover the inner wall of the sub-groove.

[0012] In some possible implementations, the metal layer includes one or more of Au, Al, Cu, and Ti.

[0013] In some possible implementations, the gas in the main gas chamber, the auxiliary gas chamber, and the first cavity includes one or more of OCS, N2O, CO, NO, SO2, H2CO, HCN, and CH3OH.

[0014] In some possible implementations, the first substrate may be a wafer, such as a silicon wafer, a glass wafer, etc.; wherein the first substrate may be a single wafer or a plurality of stacked wafers.

[0015] In some possible implementations, the first cover plate may be made of a wafer, such as a silicon wafer, a glass wafer, or the like.

[0016] The present application also provides a method for manufacturing a molecular clock waveguide, which may include: manufacturing an airbag package sealed with a target gas. Providing a first substrate, and forming a main groove and a sub-groove on the first surface of the first substrate. Placing the airbag package into the sub-groove and fixing it. Providing a first cover plate, and covering the first cover plate on the first surface under a vacuum environment to seal the main groove and the sub-groove to form a main air chamber and a sub-air chamber, respectively. Forming a notch on the shell of the airbag package from the outside of the sub-air chamber to release the target gas to the main air chamber and the sub-air chamber through the notch.

[0017] In some possible implementations, the method of manufacturing the target gas-sealed airbag package may include providing a second substrate and forming a first groove on the second substrate, providing a second cover plate and placing the second cover plate on top of the first groove in an environment of the target gas to seal the first groove and form a first cavity.

[0018] In some possible implementations, after providing a first substrate and forming a main groove and a sub-groove on a first surface of the first substrate, the manufacturing method further includes: forming a metal layer on the sidewalls and bottom of the main groove and the sub-groove.

[0019] The present application also provides a molecular clock, comprising an ASIC chip and a molecular clock waveguide provided in any of the aforementioned possible implementation methods, wherein the ASIC chip is connected to the molecular clock waveguide.

[0020] In some possible implementations, the ASIC chip is connected to the molecular clock waveguide and stacked.

[0021] The present application also provides an atomic gas chamber, which may include a first substrate, a first cover plate, and an airbag package. The first substrate has a surface provided with a primary groove and a secondary groove. The first cover plate covers the primary groove and the secondary groove to form a primary gas chamber and a secondary gas chamber, respectively, with the primary gas chamber and the secondary gas chamber communicating with each other. The airbag package is disposed within the secondary gas chamber and has a first cavity, wherein the sidewalls of the first cavity have a notch communicating with the secondary gas chamber.

[0022] In some possible implementations, in the atomic gas chamber, the airbag package includes a second substrate and a second cover plate, wherein a first groove is provided on the surface of the second substrate, and the second cover plate covers the first groove to form a first cavity.

[0023] In some possible implementations, in the above-mentioned atomic gas chamber, the first substrate has a partition wall between the main groove and the sub-groove, a gap is formed between the partition wall and the first cover plate, and the main gas chamber and the sub-gas chamber are connected through the gap.

[0024] In some possible implementations, in the atomic gas chamber, the airbag package includes a sealed glass bubble having a first cavity.

[0025] In some possible implementations, the atomic gas chamber further includes a metal layer, which covers the inner wall of the main groove. The metal layer may also cover the inner wall of the auxiliary groove.

[0026] In some possible implementations, the metal layer includes one or more of Au, Al, Cu, and Ti.

[0027] In some possible implementations, in the above-mentioned atomic gas chamber, the gas in the main gas chamber, the auxiliary gas chamber, and the first cavity includes one or more of OCS, N2O, CO, NO, SO2, H2CO, HCN, and CH3OH.

[0028] In some possible implementations, in the above-mentioned atomic gas chamber, the first substrate can be a wafer, such as a silicon wafer, a glass wafer, etc.; wherein, the first substrate can be a single wafer or a plurality of stacked wafers.

[0029] In some possible implementations, in the above-mentioned atomic gas chamber, the first cover plate may be a wafer, such as a silicon wafer, a glass wafer, etc.

[0030] The present application also provides a method for manufacturing an atomic gas chamber, which may include: manufacturing an airbag package sealed with a target gas. Providing a first substrate, and forming a main groove and a sub-groove on the first surface of the first substrate. Placing the airbag package into the sub-groove and fixing it. Providing a first cover plate, and covering the first cover plate on the first surface under a vacuum environment to seal the main groove and the sub-groove to form a main air chamber and a sub-air chamber, respectively. Forming a notch on the shell of the airbag package from the outside of the sub-air chamber to release the target gas to the main air chamber and the sub-air chamber through the notch.

[0031] In some possible implementations, in a method for fabricating an atomic gas chamber, fabricating an airbag package sealed with a target gas may include: providing a second substrate and forming a first groove on the second substrate; providing a second cover plate and placing the second cover plate on top of the first groove in an environment of the target gas to seal the first groove and form a first cavity.

[0032] In some possible implementations, after providing a first substrate and forming a main groove and a sub-groove on a first surface of the first substrate, the above-mentioned method for manufacturing an atomic gas chamber further includes: forming a metal layer on the sidewalls and bottom of the main groove and the sub-groove.

[0033] An embodiment of the present application also provides an atomic clock, which may include a light source and an atomic gas chamber provided in any of the aforementioned possible implementation methods; the light emitted by the light source is coupled to the main gas chamber in the atomic gas chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A schematic diagram of the structure of a molecular clock provided in an embodiment of the present application;

[0035] Figure 2 A schematic cross-sectional view of a MEMS molecular clock waveguide provided in an embodiment of the present application;

[0036] Figure 3 for Figure 2 Schematic diagram of the MEMS molecular clock waveguide in the figure;

[0037] Figure 4 A schematic plan view of a MEMS molecular clock waveguide provided in an embodiment of the present application;

[0038] Figure 5 A schematic structural diagram of an airbag package provided in an embodiment of the present application;

[0039] Figure 6 A schematic diagram of a partial structure of a MEMS molecular clock waveguide provided in an embodiment of the present application;

[0040] Figure 7 A flow chart of a method for manufacturing a MEMS molecular clock waveguide provided in an embodiment of the present application;

[0041] Figure 8 A schematic diagram of the manufacturing process of a MEMS molecular clock waveguide provided in an embodiment of the present application. DETAILED DESCRIPTION

[0042] To make the objectives, technical solutions, and advantages of this application more clear, the technical solutions in this application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0043] The terms "first", "second", etc. in the specification, embodiments, claims, and drawings of this application are only used for the purpose of distinguishing descriptions and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying an order. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "At least one (item)" means one or more, and "multiple" means two or more. "Installation", "connection", "connected", etc. should be understood in a broad sense, for example, it can be an electrical connection or a mechanical connection; it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, an indirect connection through an intermediate medium, or a connection between two elements. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, including a series of steps or units. Methods, systems, products, or devices are not necessarily limited to the steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to the processes, methods, products, or devices. "Up," "down," "left," "right," etc. are used only with respect to the orientation of components in the drawings. These directional terms are relative concepts and are used for relative description and clarification. They may change accordingly depending on the orientation of the components in the drawings.

[0044] An embodiment of the present application provides a molecular clock, which can also be called an on-chip molecular clock or a chip-level molecular clock. The molecular clock adopts a molecular clock waveguide with a novel structure. The molecular clock waveguide can be manufactured using micro-electro-mechanical system (MEMS) technology, hereinafter referred to as MEMS molecular clock waveguide.

[0045] It is understandable that MEMS technology is based on semiconductor processing technologies such as graphics and etching, and naturally has the characteristics of high processing precision, good consistency, and mass production, and can be applied to the miniaturization processing of molecular clock waveguides.

[0046] Of course, the molecular clock includes other device components in addition to the above-mentioned MEMS molecular clock waveguide.

[0047] For example, in some possible implementations, Figure 1As shown, in order to meet the user's needs for specific electronic systems, the molecular clock can include an ASIC chip 2 (application specific integrated circuit, an integrated circuit for special applications) on the basis of the MEMS molecular clock waveguide 1. The ASIC chip 2 is connected to the MEMS molecular clock waveguide 1. Of course, in some embodiments, in order to meet the miniaturization and high integration of the molecular clock, the ASIC chip 2 can be stacked on the MEMS molecular clock waveguide 1. Among them, two antennas 21 for receiving and sending signals can be set on the surface of the ASIC chip 2. In this case, a high-frequency signal is sent to the MEMS molecular clock waveguide through an antenna 21 to excite a specific gas in the MEMS molecular clock waveguide, causing the electrons in the specific gas to undergo energy level transitions. Since the electron transition frequency of the specific gas is fixed, it is manifested in the microwave energy spectrum as an absorption peak at a specific frequency. In this way, the detection signal is received by another antenna 21, and a long-term stable frequency source can be obtained.

[0048] Compared with the traditional mechanical pinch-off sealing method, which has the problem of poor long-term stability of airtightness, the MEMS molecular clock waveguide provided in the embodiment of the present application is manufactured using MEMS technology, seals the airbag packaging structure in the waveguide cavity, and releases the gas therein by destroying the airbag packaging structure, making it easier to control the gas pressure in the cavity, thereby ensuring the long-term stability of airtightness in the waveguide cavity on the basis of achieving miniaturization of the molecular clock.

[0049] The structure of the MEMS molecular clock waveguide provided in the embodiments of the present application is described in detail below.

[0050] Schematically, embodiments of the present application provide a MEMS molecular clock waveguide (hereinafter referred to as a waveguide). This waveguide is fabricated using MEMS technology, enabling miniaturization, high integration, and mass production of molecular clocks while reducing manufacturing costs. Furthermore, wafer-level packaging technology based on MEMS technology effectively meets the molecular clock waveguide's airtightness requirements.

[0051] Indicative, such as Figure 2 As shown, the MEMS molecular clock waveguide provided in the embodiment of the present application may include a first substrate 10 , a first cover plate 20 , and an airbag package 30 .

[0052] Figure 3 for Figure 2 Schematic diagram of the first substrate 10. Figure 2 and Figure 3As shown, a main groove 101 and a sub-groove 102 are provided on the surface of the first substrate 10 , and the main groove 101 and the sub-groove 102 can be connected. For the specific connection method, please refer to the relevant description below.

[0053] As shown, the first substrate 10 can be a wafer, such as a silicon wafer, a glass wafer (glass sheet), etc. During the manufacturing process, the main groove 101 and the auxiliary groove 102 can be manufactured on the wafer through an etching process using MEMS technology.

[0054] Of course, in some cases, due to the large depth of the grooves (101, 102), the thickness of a single wafer may not be sufficient for the production of the grooves (101, 102). In some possible implementation methods, the first substrate 10 can be a plurality of stacked silicon wafers or glass wafers.

[0055] Similarly, the first cover plate 20 may also be a wafer, such as a silicon wafer or a glass wafer (or a glass sheet), but is not limited thereto.

[0056] refer to Figure 2 As shown, MEMS technology can be used to bond the first cover plate 20 to the surface of the first substrate 10 to seal the grooves (101, 102), so as to form a main gas chamber C1 at the position of the main groove 101 and a secondary gas chamber C2 at the position of the secondary groove 102, and the main gas chamber C1 and the secondary gas chamber C2 are connected to realize the packaging of the MEMS molecular clock waveguide.

[0057] It can be understood that, compared with the traditional mechanical pinch-off sealing method, the bonding sealing method between the first substrate 10 and the first cover plate 20 can achieve long-term stability of airtightness.

[0058] As shown, in some possible implementation methods, the first cover plate 20 and the first substrate 10 can be sealed using wafer-level sealing technologies such as anodic bonding, metal eutectic bonding, and silicon-silicon bonding. While ensuring airtightness, a very narrow bonding ring width can be achieved, thereby greatly reducing the volume of the waveguide.

[0059] On this basis, reference Figure 2 and Figure 3 As shown, the airbag package 30 is disposed within the secondary air chamber C2. The airbag package 30 has a first cavity 300. A notch a is provided in the housing of the airbag package 30, connecting the first cavity 300 to the secondary air chamber C2 through the notch a. This allows the target gas stored in the first cavity 300 of the airbag package 30 to be released into the secondary air chamber C2 and the main air chamber C1 through the notch a.

[0060] Specifically, refer to Figure 5As shown, before the airbag package 30 is packaged into the auxiliary air chamber C2, a specific gas (also referred to as target gas) is sealed in the first cavity 300 of the airbag package 30, and there is no gap a on the shell of the airbag package 30. After the airbag package 30 is packaged into the auxiliary air chamber C2 through the first cover plate 20, the shell of the airbag package 30 is destroyed from the outside of the auxiliary air chamber C2 to form a gap a (refer to FIG. Figure 2 ), so that the gas in the first cavity 300 can be released into the auxiliary air chamber C2 through the gap a. Since the auxiliary air chamber C2 is connected to the main air chamber C1, the gas can further diffuse into the main air chamber C1.

[0061] That is to say, after the airbag package 30 is packaged into the auxiliary air chamber C2, by damaging the airbag package 30, the specific gas in the first cavity 300 can be diffused into the auxiliary air chamber C2, and diffused into the main air chamber C1 through the airway, thereby satisfying the molecular clock to obtain a long-term stable frequency source by detecting the specific gas in the main air chamber C1.

[0062] By adopting the above-mentioned configuration of the airbag package 30, the control of the gas pressure can be converted into the control of the volume (C1, C2), which greatly reduces the difficulty of packaging. The specific analysis is as follows:

[0063] Assume that the inner volume of the main air chamber C1 is V1, the inner volume of the auxiliary air chamber C2 is V2, the volume of the first cavity 300 is V3, the equivalent volume of the airbag wall of the airbag package 30 is V4, the airway volume is V5, the gas pressure in the first cavity 300 is P0 (before the airbag package 30 is damaged), and the target air pressure of the main air chamber C1 is P t , then:

[0064] P0V3=P t (V1+V2+V5-V4)

[0065]

[0066] Generally, V4<<V1; V5<<V1, then:

[0067]

[0068] From the above formula, we can see that the target pressure is P t This is converted into control of the cavity volume (V1, V2, V3) and the gas pressure P0 in the first cavity 300.

[0069] Related technologies also provide a MEMS molecular clock waveguide, which relies on a bonding machine for hermetic packaging, and the pressure inside the sealed cavity depends on the pressure of the bonding machine. During the bonding process, the bonding machine's built-in vacuum pump pumps the pressure inside the cavity to the device's ultimate vacuum. Furthermore, during the packaging process, the vacuum pump continuously extracts gas, which is in a dynamic state, making it difficult to control the gas pressure.

[0070] In contrast, the MEMS molecular clock waveguide in this application changes the pressure in the cavity (P t ) is converted into control of the cavity volume (V1, V2) and the gas pressure P0 in the airbag package 30, which greatly reduces the difficulty of pressure control while achieving long-term stability of airtightness.

[0071] As shown, the gas pressure P0 in the first cavity 300 can be set as needed, and this application does not limit this. For example, in some possible implementations, P0 can be 0.5 atm, 1 atm, 2 atm, 3 atm, etc.

[0072] Schematically, the target pressure P t Generally, it can be in the range of 1Pa to 100Pa. For example, in some possible implementations, P t It can be around 10Pa.

[0073] It can be understood that in the MEMS molecular clock waveguide, the main air chamber C1 serves as the waveguide cavity, and the auxiliary air chamber C2 is used to place the airbag package 30; the setting of the main air chamber C1 and the auxiliary air chamber C2 mainly depends on the shape, size, etc. of the main groove 101 and the auxiliary air chamber C2. As long as the setting of the main groove 101 and the auxiliary groove 102 can meet the requirements of the MEMS molecular clock waveguide, this application does not impose any restrictions on this.

[0074] For example, in some possible implementations, Figure 3 As shown, the main groove 101 can be an S-shaped (or serpentine) groove; the auxiliary groove 102 is arranged on the side of the main groove 101 and can be a rectangular groove.

[0075] For example, in some possible implementations, Figure 4 As shown, the main groove 101 may include two connected spiral grooves; the auxiliary groove 102 is arranged between the two spiral grooves and may be a rectangular groove, and both sides of the auxiliary groove 102 are respectively connected to the two spiral grooves.

[0076] The airbag package 30 adopts a sealing device capable of sealing gas inside. The present application does not impose any restrictions on the arrangement of the airbag package 30 , and it can be arranged as needed in practice.

[0077] For example, Figure 5 As shown, in some possible implementations, the airbag package 30 can be manufactured using MEMS technology. The airbag package 30 includes a second substrate 301 and a second cover plate 302. A first groove 300 is provided on the surface of the second substrate 301. In an atmosphere of a target gas at a certain pressure (e.g., 1 atm), the second cover plate 302 is placed over the first groove T1 to form a first cavity 300. The second substrate 301 and the second cover plate 302 can be sealed using wafer-level sealing techniques such as anodic bonding, metal eutectic bonding, and silicon-silicon bonding to ensure the airtightness of the first cavity 300.

[0078] Similar to the configuration of the first substrate 10 and the first cover plate 20, the second substrate 301 and the second cover plate 302 can also be made of silicon wafers or glass wafers. The second substrate 301 can be a single wafer or a plurality of stacked wafers.

[0079] For example, in some possible implementations, the airbag package 30 may be formed by placing a glass bulb in an atmosphere of a target gas at a certain pressure (e.g., 1 atm) and sealing it with a sealing material such as wax or epoxy resin. In other words, the airbag package 30 is a sealed glass bulb structure having a first cavity 300 formed therein.

[0080] In addition, the present application does not impose any restrictions on the target gas sealed in the first cavity 300, as long as it meets the frequency and performance requirements of the molecular clock.

[0081] Illustratively, in some possible implementations, the target gas sealed in the first cavity 300 may be one or more of OCS (carbonyl sulfide), N2O (nitrous oxide), CO (carbon monoxide), NO (nitric oxide), SO2 (sulfur dioxide), H2CO (formaldehyde), HCN (hydrogen cyanide), and CH3OH (methanol).

[0082] It should be understood that the target gas sealed in the first cavity 300 will diffuse into the entire main air chamber C1 and the auxiliary air chamber C2 after the airbag package 30 is destroyed.

[0083] In addition, the present application does not impose any restrictions on the communication method between the main air chamber C1 and the auxiliary air chamber C2, and it can be set as needed in practice.

[0084] In some possible implementations, for example, Figure 2As shown, the first substrate 10 has a partition wall 100 between the main groove 101 and the sub-groove 102. The top of the partition wall 100 and the first cover plate 20 bracket have a gap S. The main air chamber C1 and the sub-air chamber C2 are connected through the gap S, that is, the gap S is equivalent to the air channel between the main air chamber C1 and the sub-air chamber C2.

[0085] After the main groove 101 is formed on the first substrate 10 , the inner wall (including the side wall and the bottom) of the main groove 101 is relatively rough, and the microwaves in the waveguide will be scattered at the inner wall of the main groove 101 , which will cause microwave transmission loss.

[0086] Based on this, in order to reduce microwave transmission loss, some possible implementation methods are as follows: Figure 6 As shown, a metal layer 110 may be provided on the inner wall of the main groove 101 , and the metal layer 110 can reduce the roughness of the inner wall, reduce scattering, and thus reduce microwave transmission loss.

[0087] In addition, by providing the metal layer 110 on the inner wall of the main groove 101 , the reflection efficiency of microwaves at the inner wall of the main groove 101 can be improved, thereby reducing microwave leakage at the inner wall and crosstalk to other waveguides.

[0088] Similarly, a metal layer may be provided on the lower surface of the first cover plate 20 above the main groove 101 to ensure that the entire inner wall of the main gas chamber C1 is covered with the metal layer, thereby further reducing microwave transmission loss and crosstalk problems.

[0089] Taking into account the actual manufacturing process, when the metal layer 110 is manufactured on the inner wall of the main groove 101, the metal layer 110 can simultaneously cover the inner wall of the auxiliary groove 102, that is, the metal layer 110 is manufactured using a one-time manufacturing process to cover the inner walls of the main groove 101 and the auxiliary groove 102.

[0090] The present application does not limit the metal material used for the metal layer 110, and it can be set as needed in practice. For example, in some possible implementations, the metal layer 110 can include one or more metal materials selected from Au, Al, Cu, and Ti.

[0091] The present application also provides a method for manufacturing the MEMS molecular clock waveguide as described above. Figure 7 As shown, the production method may include:

[0092] Step 11: Reference Figure 5 As shown, an airbag package 30 sealed with target gas is manufactured.

[0093] In some possible implementations, reference is made to Figure 5As shown, the above step 11 may include: providing a silicon wafer or glass as a second substrate 301, using MEMS technology to process a groove (T1) on the second substrate 301 through dry etching or wet etching; then, providing another silicon wafer or glass as a second cover plate 302, performing anodically bonding the second cover plate 302 to the second substrate 301, and sealing the groove (T1) to form a first cavity 300; the entire bonding process can be performed by filling 1atm of OSC gas in the bonding machine, and after the bonding is completed, 1atm of OCS gas is stored in the sealed cavity (300). Then, dicing is performed to form Figure 5 Of course, the pressure of the OSC gas filled in the bonding machine can also be 2atm, 3atm, etc. This application does not limit this, and it can be set according to actual needs.

[0094] As shown, in some possible implementations, a glass bulb can be placed in an atmosphere of 1 atm of target gas and sealed with a sealing material such as wax or epoxy resin to form an airbag package 30. Of course, the glass bulb can also be sealed in an atmosphere of 2 atm or 3 atm of target gas, and this is not a limitation in this application. In practice, this can be set as needed.

[0095] Step 12: Reference Figure 8 As shown in (a), a first substrate 10 is provided, and a main groove 101 and a sub-groove 102 are formed on the surface of the first substrate 10 .

[0096] In some possible implementations, reference is made to Figure 8 As shown in (a), step 12 may include: taking a silicon wafer (or glass) as a first substrate 10, etching a main groove 101 and a secondary groove 102 on the silicon wafer for subsequently forming a connected main gas chamber C1 and a secondary gas chamber C2. The thickness of the partition wall 100 between the main groove 101 and the secondary groove 102 may be reduced by etching to form a certain height difference Δh with the surface of the first substrate 10, so that the subsequently formed main gas chamber C1 and the secondary gas chamber C2 can be connected at this location.

[0097] Of course, reference Figure 6 As shown, after forming the main groove 101 and the sub-groove 102 in step 12, metal Au may be deposited on the inner walls of the main groove 101 and the sub-groove 102 to form a metal layer 110 to reduce microwave transmission loss and crosstalk problems.

[0098] Step 13: Reference Figure 8 As shown in (b), the airbag package 30 is placed into the auxiliary groove 102 and fixed.

[0099] In some possible implementations, reference is made to Figure 8As shown in (b), the above step 13 may include: placing the airbag package 30 manufactured in step 11 into the auxiliary groove 102 and fixing it. The fixing method is not limited to bonding, gluing, etc.

[0100] Step 14: Reference Figure 8 As shown in (c), a first cover plate 20 is provided and covered on the surface of the first substrate 10 under a vacuum environment to seal the main groove 101 and the auxiliary groove 102 to form a main gas chamber C1 and an auxiliary gas chamber C2 respectively.

[0101] In some possible implementations, reference is made to Figure 8 As shown in (c), the above step 14 may include: pumping the pressure in the bonding machine to a high vacuum (far less than 10Pa); then, taking a glass sheet (or silicon wafer) as the first cover plate 20, performing anodic bonding with the first substrate 10 formed in step 12, and sealing the main groove 101 and the sub-groove 102 to form a main air chamber C1 and a sub-air chamber C2 respectively, thereby achieving cavity sealing.

[0102] Of course, a metal layer may be provided on the surface of one side where the first cover plate 20 covers the first substrate 10 to reduce microwave transmission loss and crosstalk problems.

[0103] Step 15: Reference Figure 8 As shown in (d), a notch a is formed on the housing of the airbag package 20 from the outside of the auxiliary air chamber C2 to release the target gas in the airbag package 30 to the main air chamber C1 and the auxiliary air chamber C2 through the notch a.

[0104] In some possible implementations, reference is made to Figure 8 As shown in (d), the above step 15 may include: irradiating the shell of the airbag package 30 through the glass (20) with a laser 40 and burning it through to form a gap a, thereby releasing the OSC gas in the airbag package 30 into the auxiliary air chamber C2 and then diffusing into the main air chamber C1. Of course, other heating, electric sintering and other methods can also be used to destroy the airbag package 30 to release the gas in the air cavity.

[0105] It should be understood that the size of the serial numbers of the above processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0106] For other relevant contents in the above-mentioned production method, you can refer to the corresponding parts in the above-mentioned structural embodiment, which will not be repeated here; for other setting structures in the above-mentioned structural embodiment, you can refer to the above-mentioned production method and related production methods for adjustment, which will not be repeated here one by one.

[0107] The aforementioned MEMS molecular clock waveguide configuration can also be applied to other MEMS devices that require control of the gas pressure in the cavity.

[0108] For example, the atomic gas chamber of an atomic clock can adopt a setting similar to the aforementioned MEMS molecular clock waveguide.

[0109] As an illustration, an embodiment of the present application also provides an atomic clock, which includes a light source and an atomic gas chamber (also called a MEMS atomic gas chamber). The light emitted by the light source is coupled into the cavity of the atomic gas chamber, and the atoms of a specific gas are excited by light, causing their electrons to transition between energy levels, thereby obtaining a long-term stable frequency source.

[0110] Among them, you can refer to Figure 2 The aforementioned atomic gas chamber may include a first substrate 10, a first cover plate 20, and an airbag package 30. The surface of the first substrate 10 is provided with a primary groove 101 and a secondary groove 102. The first cover plate 20 covers the primary groove 101 and the secondary groove 102, respectively forming a primary gas chamber C1 and a secondary gas chamber C2, with the primary gas chamber C1 and the secondary gas chamber C2 communicating with each other. The airbag package 30 is disposed within the secondary gas chamber C2 and has a first cavity 300. The sidewall of the first cavity 300 has a notch that connects to the secondary gas chamber C2.

[0111] Regarding the relevant settings and manufacturing methods of the first substrate 10, the first cover 20, and the airbag package 30 in the atomic gas chamber, you can refer to the corresponding parts in the aforementioned MEMS molecular clock waveguide, which will not be repeated here.

[0112] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A molecular clock waveguide, characterized in that: include: A first substrate, wherein a main groove and a sub-groove are arranged on a surface of the first substrate; A first cover plate, wherein the first cover plate covers the main groove and the auxiliary groove to form a main air chamber and an auxiliary air chamber respectively, and the main air chamber is communicated with the auxiliary air chamber; An airbag package is arranged in the auxiliary air chamber, the airbag package has a first cavity, and a notch is arranged on the shell of the airbag package, and the first cavity is connected with the auxiliary air chamber through the notch.

2. The molecular clock waveguide according to claim 1, characterized in that: The airbag package comprises: a second substrate and a second cover plate; A first groove is disposed on the surface of the second substrate, and the second cover plate covers the first groove to form the first cavity.

3. The molecular clock waveguide according to claim 1, characterized in that: The air bag package includes: a sealed glass bubble having the first cavity.

4. The molecular clock waveguide according to any one of claims 1 to 3, characterized in that: The first substrate has a partition wall between the main groove and the auxiliary groove, a gap is formed between the partition wall and the first cover plate, and the main air chamber and the auxiliary air chamber are connected through the gap.

5. The molecular clock waveguide according to any one of claims 1 to 4, characterized in that: The molecular clock waveguide further comprises a metal layer, and the metal layer covers the inner wall of the main groove.

6. The molecular clock waveguide according to claim 5, characterized in that: The metal layer includes one or more of Au, Al, Cu and Ti.

7. The molecular clock waveguide according to any one of claims 1 to 6, characterized in that: The gas in the main gas chamber, the auxiliary gas chamber, and the first cavity includes one or more of OCS, N2O, CO, NO, SO2, H2CO, HCN, and CH3OH.

8. The molecular clock waveguide according to any one of claims 1 to 7, characterized in that: The first substrate is made of silicon wafer or glass wafer; The first cover plate is made of a silicon wafer or a glass wafer.

9. A method for manufacturing a molecular clock waveguide, characterized in that: include: Making an airbag package sealed with a target gas; Providing a first substrate, and forming a main groove and a sub-groove on a first surface of the first substrate; placing the airbag package into the secondary groove and fixing it; Providing a first cover plate, and covering the first cover plate on the first surface in a vacuum environment to seal the main groove and the auxiliary groove to form a main air chamber and an auxiliary air chamber respectively; A notch is formed on the shell of the airbag package from the outside of the auxiliary air chamber to release the target gas to the main air chamber and the auxiliary air chamber through the notch.

10. The method for manufacturing a molecular clock waveguide according to claim 9, characterized in that: The method of manufacturing an airbag package sealed with a target gas comprises: Providing a second substrate, and forming a first groove on the second substrate; A second cover plate is provided, and the second cover plate is covered on the top of the first groove in an environment of a target gas, so as to seal the first groove to form a first cavity.

11. The method for manufacturing a molecular clock waveguide according to claim 9 or 10, characterized in that: After providing a first substrate and forming a main groove and a sub-groove on a first surface of the first substrate, the method further includes: A metal layer is formed on the sidewalls and bottom of the main groove and the sub-groove.

12. A molecular clock, characterized in that: It comprises an ASIC chip and a molecular clock waveguide as claimed in any one of claims 1 to 8, wherein the ASIC chip is connected to the molecular clock waveguide.

13. An atomic gas chamber, characterized in that: include: A first substrate, wherein a main groove and a sub-groove are arranged on a surface of the first substrate; A first cover plate, wherein the first cover plate covers the main groove and the auxiliary groove to form a main air chamber and an auxiliary air chamber respectively, and the main air chamber is communicated with the auxiliary air chamber; The airbag package is arranged in the auxiliary air chamber, the airbag package has a first cavity, and the side wall of the first cavity has a notch connected to the auxiliary air chamber.

14. The atomic gas chamber according to claim 13, characterized in that: The airbag package includes a second substrate and a second cover plate; A first groove is disposed on the surface of the second substrate, and the second cover plate covers the first groove to form the first cavity.

15. The atomic gas chamber according to claim 13 or 14, characterized in that: The substrate has a partition wall between the main air chamber and the auxiliary air chamber, a gap is formed between the partition wall and the cover plate, and the main air chamber and the auxiliary air chamber are connected through the gap.

16. An atomic clock, characterized in that: It comprises a light source and the atomic gas cell as described in any one of claims 13 to 15; the light emitted by the light source is coupled to the main gas cell in the atomic gas cell.

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