An atomic cell and a method of making the same

Abstract

Provided are an atomic cell and a manufacturing method thereof. The atomic cell comprises a first glass sheet, a second glass sheet, and a silicon wafer. The silicon wafer has a through hole penetrating through a first silicon wafer surface and a second silicon wafer surface opposite to each other. The first glass sheet covers the first silicon wafer surface, and the second glass sheet covers the second silicon wafer surface, so that the through hole forms a closed cavity. The silicon wafer further comprises a groove arranged on the first silicon wafer surface and a first modified layer arranged in the groove. One end of the groove is in communication with the cavity. The atomic cell can enable metal vapor to be oriented and condensed in the groove. A driving force generated by a surface tension difference between adjacent hierarchical groove units can pull the condensed liquid metal away from the cavity, so that condensation of the metal vapor on the inner surface of the optical window is avoided, the light transmittance of the atomic cell is not affected, the detection signal is not fluctuated or drifted, and the long-term working stability of the atomic magnetometer system is improved.

Description

Technical Field

[0001] This invention belongs to the field of micro-nano fabrication technology, specifically relating to an atomic gas chamber and its fabrication method. Background Technology

[0002] With the development of micro-nano fabrication technology and the advancement of semiconductor laser technology, the technology of realizing the interaction between lasers and atomic gas cells for detection and control at the chip scale has also developed rapidly. Devices, systems, or instruments with atomic gas cells as the core component, such as atomic frequency standards, atomic magnetometers, and atomic gyroscopes, have practical application prospects in fields such as positioning and navigation, magnetic field detection, and biomedicine. Therefore, how to achieve the fabrication of high-quality, miniaturized, and high-performance atomic gas cells has become a current research hotspot and direction.

[0003] Currently, wafer-level atomic gas cell manufacturing technology has become increasingly mature. The use of microelectromechanical systems (MEMS) manufacturing technology to prepare atomic gas cells has gradually replaced the traditional glass blowing method. The MEMS method can achieve compatibility with chip-level manufacturing and packaging processes while ensuring that the performance is not greatly degraded, thus laying the foundation for the engineering and mass production of atomic gas cells.

[0004] The atomic gas cell structure fabricated using MEMS methods consists of a three-layer structure with two planar transparent layers and a middle gas wall layer. The gas cell is filled with a buffer gas at a certain pressure and a certain amount of alkali metal element. In a heated and constant-temperature environment, the laser light passes through the transparent layer of the atomic gas cell and interacts with the heated atomic vapor to achieve optical pumping. The alkali metal element filled into the atomic gas cell is liquid at the operating temperature. To ensure sufficient atomic vapor pressure within the gas cell, the total amount of liquid alkali metal element cannot be too small. When the liquid alkali metal is in a heated environment for a long time, and because the saturated vapor pressure of alkali metal element is higher than that of other metal elements, the alkali metal vapor easily disperses, condenses, and migrates to various parts of the gas cell. This causes the alkali metal vapor to condense into droplets at the transparent window, thus blocking the transparent window and affecting the transmittance of the atomic gas cell. This leads to a change in the actual number of metal atoms interacting with the laser, resulting in fluctuations or drift in the detection signal, affecting the detection accuracy and stability of the entire system. Similar situations can occur with glass bulbs fabricated using traditional glass blowing methods. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention provides an atomic gas chamber and a method for manufacturing the same.

[0006] According to one aspect of the present invention, an atomic gas chamber is provided, the atomic gas chamber comprising: a first glass sheet, a second glass sheet, and a silicon wafer, the silicon wafer having through holes penetrating the opposing surfaces of the first and second silicon wafers; the first glass sheet covering the surface of the first silicon wafer, and the second glass sheet covering the surface of the second silicon wafer, such that the through holes form a sealed cavity; the silicon wafer further comprising a trench disposed on the surface of the first silicon wafer and a first modified layer disposed within the trench, one end of the trench communicating with the cavity.

[0007] In one example of the atomic gas chamber provided in one aspect of the above embodiments, the number of grooves is multiple, and the other end of each groove away from the cavity is interconnected.

[0008] In one example of the atomic gas chamber provided in one aspect of the above embodiments, the trench sequentially includes a first-level trench unit, a second-level trench unit, ..., a (N-1)th-level trench unit, and an Nth-level trench unit that are interconnected along a direction away from the through hole, where N is a positive integer.

[0009] In one example of the atomic gas chamber provided in one aspect of the above embodiments, the sum of the perimeters of the inner walls of the cross sections of all i-th level trench units is greater than the sum of the perimeters of the inner walls of the cross sections of all (i-1)-th level trench units, where 2≤i≤N.

[0010] In one example of the atomic gas chamber provided in one aspect of the above embodiments, the total cross-sectional area of ​​all i-th level trench units is equal to the total cross-sectional area of ​​all (i-1)-th level trench units, where 2 ≤ i ≤ N.

[0011] In one example of the atomic gas chamber provided in one aspect of the above embodiments, a groove is further included adjacent to the end of the Nth-level trench unit away from the through hole, the groove connecting the ends of each of the Nth-level trench units away from the through hole to each other.

[0012] In one example of the atomic gas chamber provided in one aspect of the above embodiments, a second modified layer is provided on the surface of the first glass plate facing the trench, the pattern of the second modified layer is the same as the pattern of the first modified layer, and the second modified layer and the first modified layer are aligned with each other.

[0013] According to another aspect of the present invention, a method for fabricating an atomic gas chamber includes: forming a plurality of trenches on the surface of a first silicon wafer and forming a first modified layer within the trenches; forming through holes penetrating the surfaces of the first and second silicon wafers, with one end of the trenches connected to the through holes; bonding a second glass sheet to the surface of the second silicon wafer; etching grooves on the surface of the first silicon wafer and / or on the surface of the first glass sheet facing the trenches, such that the other ends of each trench away from the through holes are interconnected through the grooves; filling the through holes with liquid alkali metal and a buffer gas; and bonding the first glass sheet to the surface of the first silicon wafer, such that the through holes form a sealed cavity, thereby obtaining the atomic gas chamber.

[0014] In one example of the method for fabricating an atomic gas chamber provided in another aspect of the above embodiments, the method of forming a plurality of trenches on the surface of a first silicon wafer and forming a first modified layer within the trenches specifically includes: forming a pattern of the plurality of trenches on the surface of the first silicon wafer using photolithography; etching the silicon wafer according to the trench pattern using an etching machine to form the plurality of trenches on the surface of the first silicon wafer; growing the first modified layer within each of the trenches using a sputtering process and / or a low-pressure chemical vapor deposition process; and removing the first modified layer relative to the area outside the trench region.

[0015] In one example of the method for fabricating an atomic gas chamber provided in another aspect of the above embodiments, after etching grooves on the surface of the first silicon wafer and / or on the first glass sheet, and before filling the via with liquid alkali metal and buffer gas, the method further includes: forming a second modified layer on the surface of the first glass sheet facing the grooves, the pattern of the second modified layer being the same as the pattern of the first modified layer, and the second modified layer and the first modified layer being aligned with each other;

[0016] The method for bonding the first glass sheet to the surface of the first silicon wafer includes: bonding the surface of the first glass sheet on which the second modified layer is formed to the surface of the first silicon wafer, and aligning the pattern of the second modified layer with the pattern of the first modified layer.

[0017] Beneficial Effects: The atomic gas chamber provided by this invention features grooves connected to a sealed cavity. These grooves comprise multiple hierarchical groove units, and the inner walls of the grooves are covered with a surface-wetting modified layer. Metal vapor has a lower nucleation work on the surface of this modified layer, making it more prone to condensation on the surface of the groove. Furthermore, by progressively increasing the sum of the cross-sectional perimeters of the groove units along the direction away from the cavity, the surface tension difference between adjacent groove units generates a driving force to pull the liquid metal, thereby drawing the condensed liquid metal away from the cavity. The multi-level groove design further enhances the driving force, creating a continuous traction and transport effect for the liquid metal. Additionally, grooves connect the ends of each groove away from the cavity to prevent blockage of the condensed liquid metal within the grooves. Therefore, the atomic gas cell enables metal vapor to condense in the groove, preventing metal vapor from condensing on the inner surface of the optical window and affecting the transmittance of the atomic gas cell. This avoids fluctuations or drift in the detection signal and improves the stability of the atomic magnetometer system during long-term operation. Attached Figure Description

[0018] The above and other aspects, features, and advantages of embodiments of the present invention will become clearer from the following description taken in conjunction with the accompanying drawings, in which:

[0019] Figure 1 This is a schematic diagram of the structure of the atomic gas chamber according to an embodiment of the present invention;

[0020] Figure 2 This is a plan view of an embodiment of the trench according to an embodiment of the present invention;

[0021] Figure 3 This is a schematic diagram of an embodiment of the trench arrangement and installation according to an embodiment of the present invention;

[0022] Figure 4 This is a schematic diagram of another embodiment of the trench arrangement and installation according to an embodiment of the present invention;

[0023] Figure 5 This is a flowchart of a method for fabricating an atomic gas chamber according to an embodiment of the present invention;

[0024] Figure 6 This is a process diagram of a method for fabricating an atomic gas chamber according to an embodiment of the present invention. Detailed Implementation

[0025] Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention can be implemented in many different forms, and should not be construed as limited to the specific embodiments set forth herein. Rather, these embodiments are provided to explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the various embodiments of the invention and various modifications suitable for particular intended applications.

[0026] As used herein, the term "comprising" and its variations are open terms meaning "including but not limited to". The terms "based on", "according to", etc., mean "at least partially based on" or "at least partially according to". The terms "one embodiment" and "an embodiment" mean "at least one embodiment". The term "another embodiment" means "at least one other embodiment". The terms "first", "second", etc., may refer to different or the same objects. Other definitions, whether explicit or implicit, may be included below. Unless explicitly indicated by the context, the definition of a term remains consistent throughout the specification.

[0027] As described in the background section, in existing atomic gas cells, when exposed to a heating environment for extended periods, the metal vapor within the cell disperses, condenses, and migrates to various locations within the cell. This condensation of metal vapor on the inner surface of the optical window affects the transmittance of the atomic gas cell, leading to fluctuations or drift in the detection signal and impacting the detection accuracy and stability of the entire system. Therefore, to address the numerous technical problems associated with existing atomic gas cells, this invention provides an atomic gas cell and its fabrication method.

[0028] The atomic gas chamber is provided with grooves that communicate with the sealed cavity. In a heated and constant-temperature working environment, the metal vapor generated by the liquid metal filled in the sealed cavity can be oriented and condensed in the grooves. This avoids the metal vapor from condensing on the inner surface of the optical window, which would affect the light transmittance of the atomic gas chamber and thus cause fluctuations or drift in the detection signal.

[0029] The atomic gas chamber and its manufacturing method according to embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Figure 1 This is a schematic diagram of the atomic gas chamber according to an embodiment of the present invention, with reference to... Figure 1 .

[0030] The atomic gas chamber includes a first glass plate 10, a second glass plate 20, and a silicon wafer 30. The silicon wafer 30 has a through hole penetrating a first silicon wafer surface 301 and a second silicon wafer surface 302 that are opposite each other. The first glass plate 10 covers the first silicon wafer surface 301, and the second glass plate 20 covers the second silicon wafer surface 302, so that the through hole forms a sealed cavity 31.

[0031] The silicon wafer 30 further includes a trench 40 disposed on the surface 301 of the first silicon wafer and a first modified layer 41 disposed in the trench 40, one end of the trench 40 being connected to the cavity 31.

[0032] The first glass sheet 10, the second glass sheet 20, and the silicon wafer 30 together surround the through hole, so that the through hole forms a sealed cavity 31, which is used to fill liquid alkali metal and buffer gas; the area of ​​the first glass sheet 10 opposite to the cavity 31 is an optical window, through which the laser interacts with the liquid alkali metal in the cavity 31.

[0033] The nucleation work of the gas-liquid two-phase equilibrium system of metal vapor and metal droplets is smaller on the wetting surface. Therefore, compared with the optical window surface, metal vapor has a smaller nucleation work on the modified layer surface, making it more inclined to condense on the modified layer surface. Therefore, by providing a first modified layer 41 in the trench 40, the metal vapor generated by the liquid metal filled in the cavity 31 in the heated and constant-temperature working environment can be oriented and condensed in the trench 40, avoiding the condensation of metal vapor on the inner surface of the optical window, which would affect the transmittance of the atomic gas cell, and providing an unobstructed optical window area for the interaction between laser and metal atoms.

[0034] In this embodiment, there are multiple grooves 40, and the other end of each groove 40 away from the cavity 31 is interconnected.

[0035] In this embodiment, the trench 40 sequentially includes a first-level trench unit, a second-level trench unit, ..., a (N-1)th-level trench unit, and an Nth-level trench unit that are interconnected along the direction away from the through hole, where N is a positive integer.

[0036] Furthermore, the sum of the inner perimeters of the cross-sections of all i-th level trench elements is greater than the sum of the inner perimeters of the cross-sections of all (i-1)-th level trench elements, where 2≤i≤N.

[0037] Since the surface tension within a trench unit is proportional to the perimeter of its cross-section, by progressively increasing the sum of the perimeters of the trench units' cross-sections away from the cavity 31, the surface tension difference between adjacent trench units generates a driving force to pull the liquid metal, thereby drawing the condensed liquid metal away from the cavity 31. Furthermore, the multi-stage trench design can increase the driving force, creating a continuous traction and transport effect on the liquid metal, thus transporting the liquid metal to the end of the trench 40 away from the cavity 31.

[0038] Furthermore, the total cross-sectional area of ​​all i-th level trench elements is equal to the total cross-sectional area of ​​all (i-1)-th level trench elements, where 2 ≤ i ≤ N.

[0039] The total cross-sectional area of ​​each level of the trench unit is equal, which can ensure that the liquid metal condensed in the trench 40 has an equal flux everywhere, thus avoiding turbulence of the liquid metal.

[0040] Figure 2 This is a plan view of an embodiment of the trench according to an embodiment of the present invention.

[0041] Reference Figure 2 As an example, along the direction away from cavity 31, the trenches 40 sequentially include: a first-level trench unit 40A, a second-level trench unit 40B, a third-level trench unit 40C, a fourth-level trench unit 40D, and a fifth-level trench unit 40E. The sum of the cross-sectional perimeters of all second-level trenches is greater than the sum of the cross-sectional perimeters of all first-level trenches. The sum of the cross-sectional perimeters of all third-level trenches is greater than the sum of the cross-sectional perimeters of all second-level trenches. The sum of the cross-sectional perimeters of all fourth-level trenches is greater than the sum of the cross-sectional perimeters of all third-level trenches. The sum of the cross-sectional perimeters of all fifth-level trenches is greater than the sum of the cross-sectional perimeters of all fourth-level trenches.

[0042] Continue to refer to Figure 2 Furthermore, the total cross-sectional area of ​​all second-level trenches is equal to the total cross-sectional area of ​​all first-level trenches. The total cross-sectional area of ​​all third-level trenches is equal to the total cross-sectional area of ​​all second-level trenches. The total cross-sectional area of ​​all fourth-level trenches is equal to the total cross-sectional area of ​​all third-level trenches. The total cross-sectional area of ​​all fifth-level trenches is equal to the total cross-sectional area of ​​all fourth-level trenches.

[0043] In this embodiment, a groove 50 is also included at the end of the Nth-level trench unit that is away from the through hole. The groove 50 connects the ends of each of the Nth-level trench units that are away from the through hole to each other.

[0044] When the condensed liquid metal moves within the groove 40, the groove 50 connects the other end of the groove 40 away from the cavity, which helps to maintain the air pressure balance at both ends of the groove 40, thereby allowing the liquid metal to move freely within the groove 40 and preventing blockage.

[0045] In this embodiment, a second modified layer 42 is provided on the surface of the first glass sheet 10 facing the groove 40. The pattern of the second modified layer 42 is the same as the pattern of the first modified layer 41, and the second modified layer 42 and the first modified layer 41 are aligned with each other.

[0046] The selection of the modified layer material needs to meet the following conditions: on the one hand, the modified layer material and the liquid alkali metal filled in the closed cavity will not form an alloy or have a large solid solubility in the lower temperature range on the phase diagram; on the other hand, the surface wetting of the modified layer material can make the contact angle of the alkali metal on the surface of the modified layer less than 90°.

[0047] In this embodiment, the first modified layer 41 and the second modified layer 42 are made of the same type of material, including a gold metal layer, a platinum metal layer, a silicon oxide layer, and a titanium nitride layer.

[0048] In order to make the surface of the modified layer smooth and continuously covered, the thickness of the first modified layer 41 and the second modified layer 42 should be greater than 50nm. Under this condition, the thickness of the modified layer can be designed according to actual needs. However, due to the evaporation conditions and cost of thick film, the thickness of the modified layer should not be too thick.

[0049] By forming the second modified layer 42 on the surface of the first glass plate 10 facing the groove 40, the inner wall of the groove 40 is provided with modified layer material all around, which further facilitates the orientation and condensation of metal vapor in the groove 40.

[0050] Figure 3 This is a schematic diagram of an embodiment of the trench arrangement and installation according to an embodiment of the present invention, as shown below. Figure 3 As shown, multiple grooves 40 are radially distributed around the cavity 31.

[0051] Figure 4 This is a schematic diagram of another embodiment of the trench arrangement and installation according to an embodiment of the present invention, as shown below. Figure 4 As shown, the plurality of grooves 40 are distributed on any side of the cavity 31.

[0052] According to another aspect of the present invention, a method for fabricating an atomic gas chamber is provided. Figure 5 This is a flowchart of a method for fabricating an atomic gas chamber according to an embodiment of the present invention. Figure 6 This is a process diagram of a method for fabricating an atomic gas chamber according to an embodiment of the present invention, and also refers to... Figure 5 and Figure 6 .

[0053] In step S510, a plurality of trenches 40 are formed on the surface 301 of the first silicon wafer, and a first modified layer 41 is formed in the trenches 40.

[0054] In this embodiment, before forming the trench 40, the fabrication method further includes: performing a standard double-sided cleaning of the silicon wafer 30 followed by pretreatment, specifically including: ultrasonically cleaning the silicon wafer 30 for 5 minutes using propanol and isopropanol respectively, and then coating its surface with HMDS (hexamethyldisilazane).

[0055] By performing standard double-sided cleaning and pretreatment on silicon wafer 30, the surface of silicon wafer 30 can be ensured to be clean and dry, thereby improving the adhesion of subsequent photoresist coating on the surface of silicon wafer 30.

[0056] A method for forming a plurality of trenches 40 on a first silicon wafer surface 301 and forming a first modified layer 41 within the trenches 40, according to an embodiment of the present invention, includes:

[0057] The first step involves forming a pattern of multiple trenches 40 on the surface 301 of the first silicon wafer using photolithography. Specifically, firstly, positive photoresist is uniformly spin-coated onto the surface 301 of the first silicon wafer. Then, a photoresist layer is formed by baking the photoresist using a baking machine. The baking temperature is 95°C to 110°C, and the baking time is 1 min to 3 min. Next, an exposure program is run on a contact lithography device using a first photomask with a patterned structure of multiple trenches 40 to expose the areas of the photoresist layer not covered by the first photomask. Finally, the silicon wafer 30 is placed in a developing solution for development, thereby forming a pattern of multiple trenches 40 on the surface 301 of the first silicon wafer.

[0058] The second step involves using an etching machine to etch the silicon wafer 30 according to the pattern of the plurality of trenches 40, so as to form the plurality of trenches 40 on the surface 301 of the first silicon wafer; and cleaning and removing the photoresist layer opposite to the area outside the trench 40 area.

[0059] The third step involves growing the first modified layer 41 within each of the trenches 40 using a sputtering process and / or a low-pressure chemical vapor deposition process, specifically including:

[0060] The first modified layer 41 is formed by sputtering on the surface 301 of the first silicon wafer using a sputtering process. The first modified layer 41 is a metal layer or a platinum metal layer, and the thickness of the first modified layer 41 is not less than 50 nm.

[0061] Alternatively, the first modified layer 41 may be grown on the surface 301 of the first silicon wafer using a low-pressure chemical vapor deposition process, wherein the first modified layer 41 is a silicon oxide layer or a titanium nitride layer.

[0062] Fourth step: Remove the first modified layer 41 that is opposite to the area outside the trench 40 area using chemical mechanical polishing equipment.

[0063] In step S520, a through hole is formed penetrating the first silicon wafer surface 301 and the second silicon wafer surface 302, and one end of the trench 40 is connected to the through hole.

[0064] Here, step S520 includes:

[0065] The first step involves forming the via pattern on the surface 301 of the first silicon wafer using photolithography. Specifically, firstly, positive photoresist is uniformly spin-coated onto the surface 301 of the first silicon wafer. Then, a photoresist layer is formed by baking the photoresist using a baking machine. The baking temperature is 95°C to 110°C, and the baking time is 1 min to 3 min. Next, an exposure program is run on a contact lithography device using a second photomask with the via pattern structure to expose the areas of the photoresist layer not covered by the second photomask. Finally, the silicon wafer 30 is placed in a developing solution for development, thereby forming the via pattern on the surface 301 of the first silicon wafer.

[0066] The second step involves using an etching machine to deeply etch the silicon wafer 30 according to the pattern of the via, so as to form a via penetrating the surface 301 of the first silicon wafer and the surface 302 of the second silicon wafer. Then, the photoresist layer opposite to the area outside the via is cleaned and removed. One end of the trench 40 is connected to the via.

[0067] In step S530, the second glass sheet 20 is anodicly bonded to the surface 302 of the second silicon wafer.

[0068] In step S540, grooves 50 are etched on the surface 301 of the first silicon wafer and / or on the surface of the first glass plate 10 facing the trench 40, so that the other ends of each trench 40 away from the through hole are interconnected through the grooves 50.

[0069] Both the first glass sheet 10 and the second glass sheet 20 are BF33 glass sheets.

[0070] In step S550, a second modified layer 42 is formed on the surface of the first glass sheet 10 facing the groove 40. The pattern of the second modified layer 42 is the same as the pattern of the first modified layer 41, and the second modified layer 42 and the first modified layer 41 are aligned with each other.

[0071] Here, step S550 includes:

[0072] Using the first photomask with the patterned structure of the trench 40, the second modified layer 42 is grown on the surface of the first glass sheet 10 facing the trench 40 by sputtering and / or low-pressure chemical vapor deposition; wherein the pattern of the second modified layer 42 is the same as the pattern of the first modified layer 41, and the second modified layer 42 and the first modified layer 41 are aligned with each other; furthermore, the second modified layer 42 and the first modified layer 41 are of the same kind of material.

[0073] In step S560, liquid alkali metal and buffer gas are filled into the through hole, and the first glass plate 10 is bonded to the surface 301 of the first silicon wafer to form a closed cavity 31 in the through hole, thereby obtaining the atomic gas chamber.

[0074] In one example, the alkali metal includes rubidium and cesium, and the pressure of the buffer gas is 200 Torr to 760 Torr.

[0075] The buffer gases include nitrogen, argon, and xenon (including their isotopes), and different ratios of the above-mentioned buffer gases can be mixed according to the detection requirements.

[0076] In this embodiment, the method of bonding the first glass sheet 10 to the surface 301 of the first silicon wafer includes: anodic bonding of the surface of the first glass sheet 10 on which the second modified layer 42 is formed to the surface 301 of the first silicon wafer, and aligning the pattern of the second modified layer 42 with the pattern of the first modified layer 41.

[0077] In summary, the atomic gas chamber provided by this invention features grooves connected to a sealed cavity. These grooves comprise multiple hierarchical groove units, and the inner walls of the grooves are covered with a surface-wetting modified layer. Metal vapor has a lower nucleation work on the surface of this modified layer, making it more prone to condensation on the surface of the groove. Furthermore, by progressively increasing the sum of the cross-sectional perimeters of the groove units along the direction away from the cavity, the surface tension difference between adjacent groove units generates a driving force to pull the liquid metal, thereby drawing the condensed liquid metal away from the cavity. The multi-level groove design further amplifies the driving force, creating a continuous traction and transport effect for the liquid metal. Additionally, grooves connect the ends of each groove away from the cavity to prevent blockage of the condensed liquid metal within the grooves. Therefore, the atomic gas cell enables metal vapor to condense in the groove, preventing metal vapor from condensing on the inner surface of the optical window and affecting the transmittance of the atomic gas cell. This avoids fluctuations or drift in the detection signal and improves the stability of the atomic magnetometer system during long-term operation.

[0078] The method for fabricating the atomic gas chamber provided by this invention is simple, convenient, and low in cost, and has great application prospects.

[0079] The foregoing has described specific embodiments of the invention. Other embodiments are within the scope of the appended claims.

[0080] The terms “exemplary,” “example,” etc., used throughout this specification mean “serving as an example, instance, or illustration” and do not imply “preferred” or “advantageous” than other embodiments. Detailed descriptions are included for the purpose of providing an understanding of the described techniques. However, these techniques can be practiced without these detailed descriptions. In some instances, well-known structures and apparatuses are shown in block diagram form to avoid obscuring the concepts of the described embodiments.

[0081] The optional embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the scope of the technical concept of the embodiments of the present invention, various simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all fall within the protection scope of the embodiments of the present invention.

[0082] The foregoing description of this specification is provided to enable any person skilled in the art to implement or use the content of this specification. Various modifications to the content of this specification will be apparent to those skilled in the art, and the general principles defined herein can be applied to other variations without departing from the scope of protection of this specification. Therefore, this specification is not limited to the examples and designs described herein, but is consistent with the widest scope of the principles and novel features disclosed herein.

Claims

1. An atomic gas chamber, characterized in that, The atomic gas chamber includes: a first glass plate, a second glass plate, and a silicon wafer, wherein the silicon wafer has a through hole penetrating the opposing surfaces of the first and second silicon wafers; the first glass plate covers the surface of the first silicon wafer, and the second glass plate covers the surface of the second silicon wafer, so that the through hole forms a sealed cavity. The silicon wafer further includes a trench disposed on the surface of the first silicon wafer and a first modified layer disposed in the trench, one end of the trench being connected to the cavity; The number of grooves is multiple, and the other end of each groove away from the cavity is interconnected; The trenches, along the direction away from the through hole, sequentially include interconnected first-level trench units, second-level trench units, ..., N-1-level trench units, and N-level trench units, where N is a positive integer; The atomic gas chamber also includes a groove located near the end of the Nth-level trench unit away from the through hole, the groove connecting the ends of each of the Nth-level trench units away from the through hole to each other.

2. The atomic gas chamber according to claim 1, characterized in that, The sum of the inner perimeters of the cross-sections of all i-th level trench elements is greater than the sum of the inner perimeters of the cross-sections of all (i-1)-th level trench elements, where 2 ≤ i ≤ N.

3. The atomic gas chamber according to claim 1, characterized in that, The total cross-sectional area of ​​all i-th level trench elements is equal to the total cross-sectional area of ​​all (i-1)-th level trench elements, where 2 ≤ i ≤ N.

4. The atomic gas chamber according to claim 1, characterized in that, A second modified layer is provided on the surface of the first glass sheet facing the groove. The pattern of the second modified layer is the same as that of the first modified layer, and the second modified layer and the first modified layer are aligned with each other.

5. A method for manufacturing an atomic gas chamber according to any one of claims 1 to 4, characterized in that, The manufacturing method includes: Multiple trenches are formed on the surface of a first silicon wafer, and a first modified layer is formed within the trenches; A through-hole is formed penetrating the surfaces of the first and second silicon wafers, and one end of the trench is connected to the through-hole; The second glass sheet is bonded to the surface of the second silicon wafer; Grooves are etched on the surface of the first silicon wafer and / or on the surface of the first glass sheet facing the trenches, so that the other ends of each trench away from the through hole are interconnected through the grooves; Liquid alkali metal and buffer gas are filled into the through hole, and the first glass plate is bonded to the surface of the first silicon wafer to form a sealed cavity, thereby obtaining the atomic gas chamber.

6. The manufacturing method according to claim 5, characterized in that, The method of forming a plurality of trenches on the surface of a first silicon wafer and forming a first modified layer within the trenches specifically includes: A pattern of multiple trenches is formed on the surface of the first silicon wafer using photolithography. The silicon wafer is etched using an etching machine according to the pattern of the trenches to form the plurality of trenches on the surface of the first silicon wafer. The first modified layer is grown in each of the trenches using a sputtering process and / or a low-pressure chemical vapor deposition process; The first modified layer, which is opposite to the area outside the trench region, is removed.

7. The manufacturing method according to claim 5 or 6, characterized in that, After etching grooves on the surface of the first silicon wafer and / or on the first glass sheet, and before filling the via with liquid alkali metal and buffer gas, the fabrication method further includes: forming a second modified layer on the surface of the first glass sheet facing the grooves, the pattern of the second modified layer being the same as the pattern of the first modified layer, and the second modified layer and the first modified layer being aligned with each other. The method for bonding the first glass sheet to the surface of the first silicon wafer includes: bonding the surface of the first glass sheet on which the second modified layer is formed to the surface of the first silicon wafer, and aligning the pattern of the second modified layer with the pattern of the first modified layer.

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