Atomic gas cell and method of manufacturing the same

Abstract

The present application relates to an atomic gas cell and a manufacturing method thereof. The atomic gas cell comprises: a first silicon wafer; a glass wafer located on the first silicon wafer; the glass wafer has opposite first and second surfaces, and the first surface is located at one end close to the first silicon wafer; wherein the glass wafer has a plurality of through-hole structures penetrating the first and second surfaces; the through-hole structures and the first silicon wafer form a gas cavity; an alkali metal is located in the gas cavity; a second silicon wafer is located on the second surface of the glass wafer, and the second silicon wafer completely covers the opening of the gas cavity. The atomic gas cell provided by the present application can obtain an atomic gas cell with four light transmission surfaces by arranging a plurality of through-hole structures penetrating the first and second surfaces of the glass wafer, and can meet the requirements of precise incidence and emission of double laser beams in different directions, and adapt to the requirements of flexibility and stability of the optical path of the double light scheme.

Description

Technical Field

[0001] This invention relates to the field of quantum sensing technology, and in particular to an atomic gas chamber and its manufacturing method. Background Technology

[0002] Alkali metal atom gas cells are core components of quantum sensors (such as atomic magnetometers, nuclear magnetic resonance gyroscopes, and atomic clocks). The alkali metal atoms (such as potassium, rubidium, and cesium) encapsulated within the cell can interact with lasers to achieve high-precision detection of physical parameters such as magnetic fields, angular velocities, and time. Therefore, the alkali metal atom gas cell directly determines the detection sensitivity and stability of quantum sensors, making it a crucial component for the practical application of quantum sensing technology.

[0003] With the increasing demand for miniaturization and integration, micro-atom gas cells fabricated using Micro-Electro-Mechanical Systems (MEMS) technology are gradually replacing traditional glass gas cells, becoming a core direction for promoting the miniaturization of quantum sensors. However, most current MEMS gas cell designs employ a double-sided transparent structure, processing transparent windows only on opposite sides of the atomic gas cell. This structure only allows lasers to complete incident and emitted along a single fixed direction, which has significant limitations in dual-beam SERF (Spin-Exchange Relaxation-Free Magnetometer) magnetometers and nuclear magnetic resonance gyroscopes. Specifically, the double-sided transparent structure cannot simultaneously meet the requirement of precise incident and emitted laser beams in different directions, necessitating the design of complex optical path steering structures to adapt to the dual-beam system. This leads to increased device size and integration difficulty. Furthermore, optical path deflection easily causes light intensity loss and phase shift, thus affecting measurement accuracy and making it difficult to meet the requirements of optical path flexibility and stability for dual-beam solutions. Summary of the Invention

[0004] Therefore, it is necessary to provide an atomic gas chamber to address the problem that MEMS gas chambers cannot be adapted to quantum sensors with dual-light schemes.

[0005] An atomic gas chamber includes: a first silicon wafer; a glass wafer located on the first silicon wafer; the glass wafer having opposing first and second surfaces, the first surface being located near one end of the first silicon wafer; wherein the glass wafer has a plurality of through-hole structures penetrating the first and second surfaces; the through-hole structures and the first silicon wafer constitute a gas chamber; an alkali metal located within the gas chamber; and a second silicon wafer located on the second surface of the glass wafer, the second silicon wafer completely covering the opening of the gas chamber.

[0006] In one embodiment, the atomic gas chamber further includes a gold structure located within the gas chamber and on the surface of the first silicon wafer. Since gold does not chemically react with alkali metals and has a small contact angle with them, exhibiting good wettability, setting the gold structure on the surface of the first silicon wafer enables the directional condensation of alkali metals in a high-temperature working environment. This effectively prevents alkali metals from depositing on the low-thermal-conductivity glass inner wall, ensuring light transmission around the atomic gas chamber and improving its service life.

[0007] In one embodiment, the first silicon wafer has a first size, the second silicon wafer has a second size, and the glass wafer has a third size; the third size is equal to the first size and the third size is greater than the second size. By setting the size of the glass wafer to be larger than the size of the second silicon wafer, it is beneficial to expose the cutting marks on the edge of the glass wafer, and the cutting positioning can be achieved according to the cutting marks during the cutting process.

[0008] In one embodiment, the glass wafer has dicing marks located on a second surface of the glass wafer, specifically at its edge region. Based on these dicing marks, the atomic gas chamber is diced to form multiple atomic gas chamber units with four light-transmitting surfaces. By setting dicing marks on the edge region of the glass wafer, the specific location of the through-hole structure can be marked, thereby providing a precise cutting path reference for the laser cutting process and preventing damage to the atomic gas chamber structure during laser cutting, which could lead to gas leakage within the atomic gas chamber.

[0009] In one embodiment, the sidewall tilt angle of the through-hole structure is less than or equal to 1.5°, and the inner surface roughness of the sidewall is less than or equal to 80 nm. This achieves excellent through-hole perpendicularity, significantly improving the flatness of the light-transmitting surface of the atomic gas cell; it also reduces light scattering and reflection losses, thereby increasing the light transmittance of the atomic gas cell, improving the measurement accuracy of the quantum sensor, and enabling precision measurement.

[0010] Based on this, this application embodiment also provides a method for manufacturing an atomic gas chamber, the method comprising: providing a glass wafer having opposing first and second surfaces; performing a laser process on the glass wafer to form a plurality of through-hole structures penetrating the first and second surfaces on the glass wafer; bonding the first surface of the glass wafer to a first silicon wafer, the through-hole structures and the first silicon wafer constituting a gas chamber; filling the gas chamber with an alkali metal; and bonding the second surface of the glass wafer to a second silicon wafer, the second silicon wafer completely covering the opening of the gas chamber.

[0011] In one embodiment, before bonding the first surface of the glass wafer to the first silicon wafer, the method for manufacturing the atomic gas chamber further includes: providing the first silicon wafer; performing a gold plating process on the first silicon wafer to form a plurality of spaced gold structures on the surface of the first silicon wafer. Since gold does not chemically react with alkali metals and has a small contact angle with alkali metals, exhibiting good wettability, setting gold structures on the surface of the first silicon wafer can achieve directional condensation of alkali metals in a high-temperature working environment, effectively preventing alkali metal deposition on the low thermal conductivity glass inner wall, ensuring light transmission around the atomic gas chamber, and improving the service life of the atomic gas chamber.

[0012] In one embodiment, a gold plating process is performed on the first silicon wafer to form a plurality of spaced gold structures on the surface of the first silicon wafer, including: forming a patterned photoresist layer on the surface of the first silicon wafer; depositing a gold plating material on the patterned photoresist layer and the surface of the first silicon wafer; and stripping the patterned photoresist layer and the gold plating material on the patterned photoresist layer to form the gold structures.

[0013] In one embodiment, the patterned photoresist layer is prepared by spin-coating photoresist onto the surface of the first silicon wafer and then exposing and developing it; the gold plating material is prepared by electron beam evaporation; and the patterned photoresist layer and the gold plating material on the patterned photoresist layer are peeled off in an acetone solution by ultrasonication.

[0014] In one embodiment, the glass wafer has a first alignment bonding mark, and the first silicon wafer has a second alignment bonding mark. Bonding the first surface of the glass wafer to the first silicon wafer includes: bonding the first surface of the glass wafer to the first silicon wafer according to the first alignment bonding mark on the glass wafer and the second alignment bonding mark on the first silicon wafer. The via structure and the first silicon wafer form a gas chamber, and the gold structure is located within the gas chamber. Here, when bonding the glass wafer to the first silicon wafer, the first and second alignment bonding marks can be precisely positioned to ensure accurate alignment between the glass wafer and the first silicon wafer, and to ensure that the gold structure is located within the gas chamber. Furthermore, the first alignment bonding mark can be formed simultaneously with the fabrication of the via structure, thus simplifying the manufacturing process of the atomic gas chamber, reducing production costs, and improving production efficiency.

[0015] In one embodiment, when performing a laser process on the glass wafer to form multiple through-hole structures penetrating the first and second surfaces, the method for manufacturing the atomic gas chamber further includes: forming a cutting mark on the second surface of the glass wafer, the cutting mark being located in the edge region of the glass wafer; after bonding the second surface of the glass wafer to the second silicon wafer, the method for manufacturing the atomic gas chamber further includes: performing a cutting process on the atomic gas chamber according to the cutting mark to form multiple atomic gas chamber units with four light-transmitting surfaces. Here, by setting the cutting mark on the edge region of the glass wafer, on the one hand, the specific location of the through-hole structure can be marked, thereby providing a precise cutting path reference for performing the laser cutting process, preventing damage to the structure of the atomic gas chamber during laser cutting, and causing gas leakage in the atomic gas chamber; on the other hand, the cutting mark can be formed simultaneously with the preparation of the through-hole structure, eliminating the need to set additional cutting marks on the second silicon wafer, which simplifies the manufacturing process of the atomic gas chamber, reduces production costs, and improves production efficiency.

[0016] In one embodiment, a laser process is performed on the glass wafer, including: performing a water-guided laser process on the glass wafer to form a plurality of through-hole structures penetrating the first surface and the second surface on the glass wafer. The sidewall tilt angle of the through-hole structure is less than or equal to 1.5°, and the inner surface roughness of the sidewall is less than or equal to 80 nm. This achieves excellent through-hole perpendicularity, significantly improves the flatness of the light-transmitting surface of the atomic gas cell, reduces light scattering and reflection losses, thereby improving the transmittance of the atomic gas cell, enhancing the measurement accuracy of the quantum sensor, and enabling precision measurement.

[0017] The atomic gas cell and its manufacturing method provided in this application, by setting multiple through-hole structures penetrating the first and second surfaces on a glass wafer, with each through-hole structure having four sidewalls, can achieve an atomic gas cell with four light-transmitting surfaces based on the light transmittance of the glass wafer. This four-sided light-transmitting atomic gas cell simultaneously meets the requirements for precise incident and exit of dual-beam lasers in different directions, eliminating the need for additional complex optical path steering structures to adapt to the dual-beam system. This allows it to meet the requirements of dual-beam schemes for optical path flexibility and stability. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1A cross-sectional structural schematic diagram of the atomic gas chamber provided in an embodiment of this application;

[0020] Figure 2 A cross-sectional structural schematic diagram of the atomic gas chamber unit provided in an embodiment of this application;

[0021] Figure 3 A three-dimensional structural schematic diagram of the atomic gas chamber unit provided in the embodiments of this application;

[0022] Figure 4 This is a schematic diagram of the structure of a glass wafer provided in an embodiment of this application;

[0023] Figure 5 This is a schematic diagram of the structure of the first silicon wafer provided in an embodiment of this application;

[0024] Figure 6 This is a schematic diagram of the structure of a glass wafer located on a first silicon wafer, provided in an embodiment of this application.

[0025] Figure 7 This is a schematic diagram of the structure of the second silicon wafer located on the glass wafer, as provided in an embodiment of this application.

[0026] Figure 8 A schematic flowchart illustrating the manufacturing method of the atomic gas chamber provided in this application embodiment;

[0027] Figures 9 to 14 This is a cross-sectional structural diagram of the atomic gas chamber during the manufacturing process, provided in an embodiment of this application.

[0028] In the figure: 10, glass wafer; 11, through-hole structure; 20, first silicon wafer; 21, gold structure; 22, alkali metal; 23, protective gas; 30, second silicon wafer; 40, gas chamber; 50, atomic gas chamber unit; 101, first surface; 102, second surface; 201, patterned photoresist layer; 202, gold plating material. Detailed Implementation

[0029] To facilitate understanding of the present invention, it will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. Rather, these embodiments or examples are provided to make the disclosure of the present invention more thorough and complete.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments or examples only and is not intended to limit the invention. The optional scope of the term "and / or" as used herein includes any one of two or more of the related listed items, as well as any and all combinations of the related listed items, including any two related listed items, any more related listed items, or a combination of all related listed items.

[0031] In this invention, numerical ranges are involved. Unless otherwise specified, the numerical ranges are considered continuous and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe features or characteristics, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are included.

[0032] In related technologies, the process flow for MEMS atomic gas chambers includes: First, performing a dry or wet etching process on a silicon wafer to form silicon vias; then, bonding the silicon wafer to a first glass wafer (silicon-glass first anodic bonding), with the silicon vias and the first glass wafer forming a gas chamber; next, filling the gas chamber with alkali metal; then, bonding the silicon wafer to a second glass wafer (silicon-glass second anodic bonding), forming a glass-silicon-glass structure; finally, cutting the glass-silicon-glass structure (heterogeneous material cutting) to obtain the MEMS atomic gas chamber. It is evident that the atomic gas chamber prepared using the above process only has light-transmitting windows fabricated on two opposite sides of the atomic gas chamber. This structure only allows lasers to complete incident and emitted along a single fixed direction, and cannot simultaneously meet the requirement of precise incident and emitted dual-beam lasers along different directions.

[0033] Based on this, the embodiments of this application provide an atomic gas chamber. Figure 1 Please refer to the schematic cross-sectional view of the atomic gas chamber provided in the embodiments of this application. Figure 1 The atomic gas chamber includes:

[0034] First silicon wafer 20;

[0035] A glass wafer 10 is located on a first silicon wafer 20; the glass wafer 10 has a first surface 101 and a second surface 102 opposite to each other, the first surface 101 being located near one end of the first silicon wafer 20; wherein, the glass wafer 10 has a plurality of through-hole structures 11 penetrating the first surface 101 and the second surface 102; the through-hole structures 11 and the first silicon wafer 20 constitute a gas chamber 40;

[0036] Alkali metal 22 is located within gas chamber 40;

[0037] The second silicon wafer 30 is located on the second surface 102 of the glass wafer 10, and the second silicon wafer 30 completely covers the opening of the gas chamber 40.

[0038] It is understood that the atomic gas cell provided in this application, by setting multiple through-hole structures 11 penetrating the first surface 101 and the second surface 102 on the glass wafer 10, and the through-hole structure 11 has four sidewalls, can obtain an atomic gas cell with four light-transmitting surfaces based on the light transmittance of the glass wafer 10. The four-sided light-transmitting atomic gas cell simultaneously meets the requirements of precise incident and exit of dual-beam lasers in different directions, without the need for additional complex optical path steering structures to adapt to the dual-beam system, and thus can adapt to the requirements of optical path flexibility and stability of the dual-beam scheme.

[0039] In some embodiments, the glass wafer 10 may be a BF33 glass wafer; in the embodiments of this application, the glass wafer 10 may be a 4-inch BF33 glass wafer, and the thickness of the glass wafer 10 may be 3 mm.

[0040] Figure 2 A cross-sectional structural schematic diagram of the atomic gas chamber unit provided in an embodiment of this application; Figure 3 A three-dimensional structural schematic diagram of the atomic gas chamber unit provided in the embodiments of this application; Figure 4 This is a schematic diagram of the structure of a glass wafer provided in an embodiment of this application.

[0041] In some embodiments, please refer to Figures 2 to 4 The glass wafer 10 has a cutting mark C, which is located on the second surface 102 of the glass wafer 10 and in the edge region of the glass wafer 10. According to the cutting mark C, the atomic gas cells are cut to form a plurality of atomic gas cell units 50 with four light-transmitting surfaces (e.g., Figure 3 (As shown). Based on the cutting mark C, the area where a single gas chamber 40 is located can be cut as a cutting unit to obtain multiple atomic gas chamber units 50 with four light-transmitting surfaces. The four-sided light-transmitting atomic gas chamber unit 50 can simultaneously meet the requirements of precise incident and exit of dual-beam lasers in different directions, without the need for additional complex optical path steering structures to adapt to the dual-beam system. This allows it to meet the requirements of dual-beam schemes for optical path flexibility and stability.

[0042] It should be noted that the glass wafer 10 may include a central region and an edge region; the central region refers to the area where multiple through-hole structures 11 are located; the edge region refers to the area outside the central region. Here, the cutting mark C can mark the specific location of the through-hole structure 11, thereby providing a precise cutting path reference for performing the laser cutting process, preventing damage to the structure of the atomic gas chamber during laser cutting, and preventing gas leakage in the atomic gas chamber.

[0043] It should be noted that in related technologies, the bonding wafer scheme of glass wafer + silicon wafer + glass wafer is used in the manufacturing process of the atomic gas chamber. Based on the light transmittance of the glass wafer, the edge position of the hole inside the atomic gas chamber can be seen during the laser cutting process, and the corresponding cutting path is then made according to the position of the hole. However, in this embodiment, the opacity of the second silicon wafer 30 means that the edge position of the through-hole structure cannot be directly seen during the laser cutting process. Therefore, by setting a cutting mark C on the edge area of ​​the glass wafer 10, the specific position of the through-hole structure 11 can be marked, and the cutting path can be determined.

[0044] Figure 5 This is a schematic diagram of the structure of the first silicon wafer provided in an embodiment of this application; Figure 6 This is a schematic diagram of the structure of a glass wafer located on a first silicon wafer, provided in an embodiment of this application. Figure 7 This is a schematic diagram of the structure of the second silicon wafer located on the glass wafer, as provided in an embodiment of this application.

[0045] In some embodiments, please refer to Figures 4 to 7 The first silicon wafer 20 has a first size, the second silicon wafer 30 has a second size, and the glass wafer 10 has a third size; the third size is equal to the first size and the third size is greater than the second size. By setting the size of the glass wafer 10 to be larger than the size of the second silicon wafer 30, it is beneficial to expose the cutting mark C on the edge of the glass wafer 10. During the cutting process, the cutting positioning can be achieved according to the cutting mark C.

[0046] In some embodiments, please refer to Figure 7 The second silicon wafer 30 covers the second surface 102 of the glass wafer 10, and the cutting mark C is located in the area on the second surface 102 of the glass wafer 10 that is not covered by the second silicon wafer 30.

[0047] In this embodiment, the first silicon wafer 20 can be a 4-inch silicon wafer with a thickness of 0.5 mm; the second silicon wafer 30 can be a 3-inch silicon wafer with a thickness of 0.5 mm; in actual operation, a wafer-level bonding scheme of 3-inch silicon wafer + 4-inch glass wafer + 4-inch silicon wafer can be adopted.

[0048] In some embodiments, please refer to Figure 4 The second surface 102 of the glass wafer 10 also has a first alignment and bonding mark A, which is located in the edge region of the glass wafer 10; please refer to Figure 5 The first silicon wafer 20 has a second alignment bonding mark B. The alignment bonding mark can also be called a "bonding positioning line" or "positioning alignment line". The first alignment bonding mark A and the second alignment bonding mark B are used to accurately position the glass wafer 10 and the first silicon wafer 20 during bonding, ensuring the precise alignment of the glass wafer 10 and the first silicon wafer 20.

[0049] In some embodiments, please refer to Figure 4 Multiple through-hole structures 11 are spaced apart on the glass wafer 10. The multiple through-hole structures 11 can be arranged in an array and arranged in n rows and m columns, where n and m are integers greater than 1. The through-hole structure 11 can be a square hole structure, and the distance between two adjacent through-hole structures 11 can be equal to or greater than the width of the through-hole structure 11.

[0050] In some specific embodiments, the through-hole structure 11 can be a square hole structure, and the ratio of the distance between two adjacent through-hole structures 11 to the width of the through-hole structure 11 can be 1:1. In this way, the arrangement density of multiple through-hole structures 11 can be reasonably set, which provides greater flexibility for cutting path planning while avoiding the accumulation of heat generated during subsequent cutting processes in adjacent areas.

[0051] In some embodiments, please refer to Figure 1 The sidewall tilt angle of the through-hole structure 11 is less than or equal to 1.5°, and the inner surface roughness (Ra) of the sidewall of the through-hole structure 11 is less than or equal to 80 nm. Thus, the sidewall tilt angle of the through-hole structure 11 being less than or equal to 1.5° achieves excellent through-hole perpendicularity, significantly improving the flatness of the light-transmitting surface of the atomic gas cell; the inner surface roughness of the sidewall of the through-hole structure 11 being less than or equal to 80 nm mitigates the light scattering and reduced transmittance caused by rough surfaces on the sidewalls; the through-hole structure 11 has a small sidewall tilt angle and inner surface roughness, which reduces light scattering and reflection losses, thereby improving the transmittance of the atomic gas cell, enhancing the measurement accuracy of the quantum sensor, and enabling precise measurement.

[0052] In some embodiments, please refer to Figure 1 The atomic gas chamber also includes a gold structure 21, located within the gas chamber 40 and on the surface of the first silicon wafer 20.

[0053] It should be noted that the atomic gas chamber requires heating to bring the alkali metal 22 inside to a gaseous state and maintain a stable atomic vapor environment during operation. It typically operates at high temperatures of 100℃-180℃ for extended periods. However, the significant difference in thermal conductivity between silicon and glass leads to a distinct temperature gradient between different material regions during operation. The glass layer, with its lower thermal conductivity, becomes the "low-temperature zone" inside the chamber. After prolonged high-temperature operation, the alkali metal 22 vapor inside the atomic gas chamber easily condenses and deposits on the cooler inner surface of the glass layer. This condensation blocks the light transmission channels of the glass layer, reducing light transmittance and consequently decreasing the signal detection accuracy of the quantum sensor, severely impacting the long-term stable performance of the equipment.

[0054] Therefore, in this embodiment, a gold structure 21 is formed on the surface of the first silicon wafer 20. Based on the characteristics of gold and alkali metal 22, specifically, gold does not chemically react with alkali metal 22 and has a small contact angle with alkali metal 22, exhibiting good wettability. Compared to the glass layer surface, alkali metal 22 droplets spread more easily on the gold surface to form a thin layer, enabling directional condensation of alkali metal 22 in a high-temperature working environment. This effectively prevents alkali metal 22 from depositing on the low thermal conductivity glass inner wall, ensuring the light transmittance around the atomic gas chamber and improving its service life. This solves the problem in existing atomic gas chambers where alkali metal 22 deposition on the glass light-transmitting surface reduces the detection signal intensity due to long-term operation in a high-temperature environment.

[0055] In some embodiments, the via structure 11 is a structure that penetrates through the glass wafer 10, so the via structure 11 can expose the gold structure 21 on the surface of the first silicon wafer 20; or, the gold structure 21 is located at the bottom of the gas chamber 40.

[0056] In some specific embodiments, the surface area of ​​the gold structure 21 is smaller than the opening area of ​​the through-hole structure 11; the thickness of the gold structure 21 is smaller than the thickness of the glass wafer 10; in the embodiments of this application, the thickness of the gold structure 21 can be 200nm.

[0057] In some embodiments, the alkali metal 22 in the gas chamber 40 can be a rubidium alloy; the gas chamber 40 can also be filled with a protective gas 23, such as nitrogen; alkali metal atoms are chemically reactive and readily react with oxygen in the air. Filling with nitrogen can isolate oxygen, preventing the alkali metal atoms from oxidizing and deteriorating, thereby maintaining their chemical stability and activity. Furthermore, in the atomic gas chamber, collisions between alkali metal atoms and the gas chamber 40 can lead to a loss of coherence, affecting the accuracy and stability of the experiment. Filling with nitrogen as a buffer gas can reduce the collision frequency between alkali metal atoms and the gas chamber 40, thereby reducing collision relaxation.

[0058] Based on this, embodiments of this application also provide a method for manufacturing an atomic gas chamber. Figure 8A schematic flowchart illustrating the manufacturing method of the atomic gas chamber provided in this application embodiment; as shown in the figure, the manufacturing method of the atomic gas chamber includes:

[0059] Step S101: Provide a glass wafer having opposing first and second surfaces;

[0060] Step S102: Perform a laser process on the glass wafer to form a plurality of through-hole structures penetrating the first and second surfaces on the glass wafer;

[0061] Step S103: The first surface of the glass wafer is bonded to the first silicon wafer, and the through-hole structure and the first silicon wafer form a gas chamber.

[0062] Step S104: Fill the gas chamber with alkali metal;

[0063] In step S105, the second surface of the glass wafer is bonded to the second silicon wafer, and the second silicon wafer completely covers the opening of the gas chamber.

[0064] It is understood that the method for manufacturing the atomic gas cell provided in this application involves setting multiple through-hole structures penetrating the first and second surfaces on a glass wafer. These through-hole structures have four sidewalls, and based on the light transmittance of the glass wafer, an atomic gas cell with four light-transmitting surfaces can be obtained. This four-sided light-transmitting atomic gas cell simultaneously meets the requirements for precise incident and exit of dual-beam lasers in different directions, eliminating the need for additional complex optical path steering structures to adapt to the dual-beam system. This allows it to meet the requirements of dual-beam schemes for optical path flexibility and stability.

[0065] It should also be understood that although the steps in the above flowchart are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Moreover, at least some of the steps in the above flowchart may include multiple steps or stages, and these steps or stages are not necessarily completed at the same time, nor are they necessarily performed sequentially.

[0066] Figures 9 to 14 This is a cross-sectional structural diagram of the atomic gas chamber provided in the embodiments of this application during the manufacturing process. Below, in conjunction with... Figures 9 to 14 The manufacturing method of the atomic gas chamber provided in the embodiments of this application and its beneficial effects will be further described in detail.

[0067] First, please refer to Figure 9 Step S101 is performed to provide a glass wafer 10, which has a first surface 101 and a second surface 102 opposite to each other.

[0068] In some embodiments, the glass wafer 10 may be a BF33 glass wafer; in the embodiments of this application, the glass wafer 10 may be a 4-inch BF33 glass wafer, and the thickness of the glass wafer 10 is 3mm.

[0069] Then, please continue to refer to Figure 9 In step S102, a laser process is performed on the glass wafer 10 to form a plurality of through-hole structures 11 penetrating the first surface 101 and the second surface 102 on the glass wafer 10.

[0070] In some embodiments, please refer to Figure 9 A laser process is performed on the glass wafer 10, including: performing a water-guided laser process on the glass wafer 10 to form multiple through-hole structures 11 penetrating the first surface 101 and the second surface 102 on the glass wafer 10. The sidewall tilt angle of the through-hole structure 11 is less than or equal to 1.5°, and the inner surface roughness of the sidewall of the through-hole structure 11 is less than or equal to 80 nm. Thus, the sidewall tilt angle of the through-hole structure 11 being less than or equal to 1.5° achieves excellent through-hole perpendicularity, significantly improving the flatness of the light-transmitting surface of the atomic gas cell; the inner surface roughness of the sidewall of the through-hole structure 11 being less than or equal to 80 nm can mitigate the scattering of light at the sidewall caused by the rough surface, reducing the light transmittance; the through-hole structure 11 has a small sidewall tilt angle and inner surface roughness, which can reduce light scattering and reflection losses, thereby improving the light transmittance of the atomic gas cell, improving the measurement accuracy of the quantum sensor, and achieving precision measurement.

[0071] In some embodiments, before performing laser processing on the glass wafer 10, the method for manufacturing the atomic gas cell further includes forming a sacrificial layer on the surface of the glass wafer 10; the sacrificial layer may be a silicon wafer, and the thickness of the sacrificial layer may be 0.2 mm.

[0072] Understandably, the sacrificial layer serves as a protective layer for the glass wafer 10. During subsequent laser processing, the sacrificial layer protects the underlying glass wafer 10 from damage caused by laser burning or edge chipping. By setting a sacrificial layer on the glass wafer 10, the surface finish of the glass wafer 10 obtained by laser etching is comparable to that obtained by dry etching.

[0073] It should be noted that water-guided laser technology is a laser process that utilizes the characteristic of water flow to constrain laser energy, precisely controlling the beam path to achieve micron-level processing accuracy. During water-guided laser cutting, the water flow acts as a light-guiding medium and also washes away molten material and debris, reducing contaminant deposition. This results in a significantly better sidewall surface quality for the cut through-hole structure 11 compared to traditional processing methods, achieving high cleanliness requirements without subsequent polishing. When performing water-guided laser technology on glass wafers 10, optimizing process parameters such as pulse energy, scanning speed, and water flow pressure can further reduce the melting and re-solidification defects of the through-hole structure 11, significantly lowering the sidewall roughness. This reduces light scattering and reflection losses, thereby increasing the transmittance of the atomic gas chamber, improving the measurement accuracy of the quantum sensor, and enabling precision measurement.

[0074] In some embodiments, please refer to Figure 4 Multiple through-hole structures 11 are spaced apart on the glass wafer 10, and the multiple through-hole structures 11 can be arranged in an array; the through-hole structure 11 can be a square hole structure, and the distance between two adjacent through-hole structures 11 can be equal to or greater than the width of the through-hole structure 11.

[0075] In some embodiments, please refer to Figure 4 When performing a laser process on the glass wafer 10 to form a plurality of through-hole structures 11 penetrating the first surface 101 and the second surface 102 on the glass wafer 10, the method for manufacturing the atomic gas chamber further includes: forming a cutting mark C on the second surface 102 of the glass wafer 10, the cutting mark C being located in the edge region of the glass wafer 10.

[0076] Here, the cutting mark C can mark the specific location of the through-hole structure 11, thereby providing a precise cutting path reference for performing the laser cutting process, preventing damage to the structure of the atomic gas chamber during the laser cutting process, which could lead to gas leakage in the atomic gas chamber. In addition, the cutting mark C can be formed at the same time as the through-hole structure 11 is prepared, without the need to set additional cutting marks on the second silicon wafer 30, which can simplify the manufacturing process of the atomic gas chamber, reduce production costs, and improve production efficiency.

[0077] In some embodiments, please refer to Figure 4 When performing a laser process on the glass wafer 10 to form a plurality of through-hole structures 11 penetrating the first surface 101 and the second surface 102 on the glass wafer 10, the method for manufacturing the atomic gas cell further includes: forming a first alignment and bonding mark A on the second surface 102 of the glass wafer 10, wherein the first alignment and bonding mark A is located in the edge region of the glass wafer 10.

[0078] The first alignment and bonding mark A is used for precise positioning when bonding the glass wafer 10 to the first silicon wafer 20, ensuring the precise alignment of the glass wafer 10 and the first silicon wafer 20.

[0079] In this embodiment, the first alignment and bonding mark A and the cutting mark C are formed simultaneously with the formation of the through-hole structure 11. This simplifies the fabrication process of the atomic gas chamber, reduces production costs, and improves production efficiency. Of course, in some other embodiments, the first alignment and bonding mark A and the cutting mark C may also be formed before or after the formation of the through-hole structure 11, and this application does not specifically limit this.

[0080] Next, please refer to Figure 13 In step S103, the first surface 101 of the glass wafer 10 is bonded to the first silicon wafer 20, and the through-hole structure 11 and the first silicon wafer 20 form a gas chamber 40.

[0081] In some embodiments, please refer to Figure 12 Before bonding the first surface 101 of the glass wafer 10 to the first silicon wafer 20, the method for manufacturing the atomic gas cell further includes: providing the first silicon wafer 20; performing a gold plating process on the first silicon wafer 20 to form a plurality of spaced gold structures 21 on the surface of the first silicon wafer 20.

[0082] In this embodiment, a gold structure 21 is formed on the surface of a first silicon wafer 20. The resulting atomic gas cell, during operation, leverages the properties of gold and alkali metal 22 to achieve directional condensation of the alkali metal 22 in a high-temperature working environment. This effectively prevents the alkali metal 22 from depositing on the low-thermal-conductivity glass inner wall, ensuring the light transmittance around the atomic gas cell and improving its lifespan. This solves the problem in existing atomic gas cells where long-term operation in a high-temperature environment leads to alkali metal 22 deposition on the glass light-transmitting surface, reducing the detection signal intensity.

[0083] In some embodiments, please refer to Figures 10 to 12 The specific steps of performing a gold plating process on the first silicon wafer 20 to form a plurality of spaced gold structures 21 on the surface of the first silicon wafer 20 may include: first, forming a patterned photoresist layer 201 on the surface of the first silicon wafer 20; then, depositing a gold plating material 202 on the patterned photoresist layer 201 and the surface of the first silicon wafer 20; and finally, peeling off the patterned photoresist layer 201 and the gold plating material 202 located on the patterned photoresist layer 201 to form the gold structures 21.

[0084] In some specific embodiments, the patterned photoresist layer 201 can be prepared by spin-coating photoresist on the surface of the first silicon wafer 20 and then exposing and developing it; the gold plating material 202 can be prepared by electron beam evaporation; the patterned photoresist layer 201 and the gold plating material 202 on the patterned photoresist layer 201 can be peeled off by ultrasonication in an acetone solution.

[0085] In some embodiments, the specific steps for forming a patterned photoresist layer 201 on the surface of the first silicon wafer 20 may include: first, performing an RCA cleaning pretreatment on the silicon wafer to remove surface impurities to ensure photoresist adhesion; then, using a spin-coating process to uniformly spin-coat positive photoresist onto the surface of the first silicon wafer 20 to form a photoresist layer; pre-baking the first silicon wafer 20 on a hot plate and transferring a specific pattern to the photoresist layer using a laser direct-write lithography device; and finally, immersing the first silicon wafer 20 in a developer solution at room temperature to remove the photoresist in the exposed areas, thus forming a patterned photoresist layer 201 on the surface of the first silicon wafer 20 that meets the requirements for subsequent gold film deposition, providing a foundation for subsequent gold film patterning. Here, the RCA cleaning pretreatment refers to the core wet chemical cleaning technology used in semiconductor manufacturing to remove contaminants from the wafer surface.

[0086] In some embodiments, a gold plating material 202 (gold film deposition) is deposited on the surface of the patterned photoresist layer 201 and the first silicon wafer 20. Specifically, an electron beam evaporation process can be used to deposit a uniform gold plating material 202 on both the retained and exposed areas of the patterned photoresist layer 201 on the surface of the first silicon wafer 20, in preparation for the subsequent stripping of the patterned photoresist layer 201 to obtain a gold structure 21 (gold film layer) with a specific pattern.

[0087] In some embodiments, the specific steps of lifting off the patterned photoresist layer 201 may include: placing the first silicon wafer 20 after gold film deposition into an acetone solution and performing ultrasonic lifting. By utilizing the dissolving effect of acetone on the photoresist, the photoresist in the unexposed area and the gold film attached thereto can be removed, leaving only the gold pattern in the exposed area after development, thereby achieving the patterning of the gold film and obtaining a gold structure 21 that conforms to the design.

[0088] In some embodiments, please refer to Figure 5 Before performing a gold plating process on the first silicon wafer 20, the method further includes performing a laser process on the first silicon wafer 20 to form a second alignment and bonding mark B on the first silicon wafer 20.

[0089] In some embodiments, please refer to Figures 4 to 6 , Figure 13The glass wafer 10 has a first alignment and bonding mark A, and the first silicon wafer 20 has a second alignment and bonding mark B. Bonding the first surface 101 of the glass wafer 10 to the first silicon wafer 20 includes: bonding the first surface 101 of the glass wafer 10 to the first silicon wafer 20 according to the first alignment and bonding mark A on the glass wafer 10 and the second alignment and bonding mark B on the first silicon wafer 20. The through-hole structure 11 and the first silicon wafer 20 form a gas chamber 40, and the gold structure 21 is located within the gas chamber 40. Specifically, when aligning the first silicon wafer 20 with the glass wafer 10 having the through-hole structure 11 (first alignment and bonding), the first alignment and bonding mark A and the second alignment and bonding mark B can be precisely positioned to ensure that the gold structure 21 on the first silicon wafer 20 precisely matches the position of the through-hole structure 11 on the glass wafer 10, ensuring that the gold structure 21 is located within the gas chamber 40; then, an anodic bonding process can be used to complete the first alignment and bonding.

[0090] In some embodiments, when bonding the first surface 101 of the glass wafer 10 to the first silicon wafer 20, the bonding temperature can be set to 350°C-400°C, and the bonding voltage can be set to 800V-1000V; for example, the bonding temperature can be 360°C, 370°C, 380°C, or 390°C, and the bonding voltage can be 830V, 850V, 870V, 900V, 930V, 950V, or 970V, etc., without specific limitations. This allows the first silicon wafer 20 and the glass wafer 10 to form a strong bond at the interface, completing the initial structural encapsulation and providing a basis for the subsequent filling of alkali metals and protective gases into a sealed space.

[0091] If the bonding temperature and bonding voltage are too low, the bonding reaction may be incomplete, leading to voids at the bonding interface and reduced bonding strength. Conversely, if the bonding temperature and bonding voltage are too high, they may adversely affect the structure and performance of the subsequently prepared atomic chambers. Therefore, a bonding temperature of 350℃-400℃ and a bonding voltage of 800V-1000V are chosen to achieve optimal bonding results, providing a foundation for the subsequent filling of the sealed space with alkali metals and protective gases.

[0092] Next, please refer to Figure 14 Step S104 is executed, in which alkali metal 22 is filled into the gas chamber 40.

[0093] In some embodiments, a small amount of alkali metal 22 may be filled in the through-hole structure 11 of the glass wafer 10 within an anaerobic glove box environment; the alkali metal 22 may be a rubidium alloy.

[0094] It should be noted that the anaerobic glove box environment refers to a closed experimental environment where the oxygen and moisture content inside the chamber is reduced to extremely low levels through a sealed structure and gas purification system. Alkali metal 22 is filled into the anaerobic glove box environment because it has extremely high chemical reactivity and readily reacts with oxygen and moisture in the air. In the anaerobic glove box environment, through continuous gas circulation and purification, the oxygen and moisture content is reduced to extremely low levels, effectively preventing contact between the alkali metal 22 and oxygen and moisture. This ensures that the alkali metal 22 maintains its chemical stability and activity during filling and proportioning, avoiding experimental failures or safety hazards caused by deterioration and inactivation.

[0095] In some embodiments, please refer to Figure 1 During the filling process of alkali metal 22, protective gas 23, such as nitrogen molecules, can also be filled into the gas chamber 40.

[0096] Finally, please refer to Figure 1 In step S105, the second surface 102 of the glass wafer 10 is bonded to the second silicon wafer 30 (second bonding), and the second silicon wafer 30 completely covers the opening of the gas chamber 40.

[0097] In some embodiments, before bonding the second surface 102 of the glass wafer 10 to the second silicon wafer 30, the second silicon wafer 30 may be subjected to RCA cleaning pretreatment to remove surface impurities.

[0098] In some embodiments, the second bonding can be performed using an anodic bonding process under a certain nitrogen pressure atmosphere, achieving wafer-level co-sealing of the alkali metal 22 and the protective gas 23, ensuring that the internal alkali metal 22 and protective gas 23 do not leak, and providing a stable working environment for the gas chamber. It is understood that anodic bonding under a nitrogen atmosphere, with nitrogen as an inert gas, can effectively isolate oxygen and moisture, prevent oxidation and contamination of the material surface, reduce defects such as bubbles and impurities at the bonding interface, and improve bonding strength.

[0099] In some embodiments, when bonding the second surface 102 of the glass wafer 10 to the second silicon wafer 30, the bonding temperature can be set to 350℃-400℃, and the bonding voltage can be set to 800V-1000V; for example, the bonding temperature can be 360℃, 370℃, 380℃, or 390℃, and the bonding voltage can be 830V, 850V, 870V, 900V, 930V, 950V, or 970V, etc., without specific limitations. This allows the second silicon wafer 30 and the glass wafer 10 to form a strong bond at the interface, completing wafer-level encapsulation and preventing leakage of the alkali metal 22 and protective gas 23.

[0100] If the bonding temperature and bonding voltage are too low, the bonding reaction may be incomplete, resulting in voids at the bonding interface and reduced bonding strength. If the bonding temperature and bonding voltage are too high, it may damage the alkali metal 22 in the atomic gas chamber. Therefore, selecting a bonding temperature of 350℃-400℃ and a bonding voltage of 800V-1000V can achieve the best bonding effect.

[0101] In some embodiments, please refer to Figure 7 After bonding the second surface 102 of the glass wafer 10 to the second silicon wafer 30, the method for manufacturing the atomic gas cell may further include: performing a cutting process on the atomic gas cell according to the cutting mark C to form a plurality of atomic gas cell units 50 having four light-transmitting surfaces (e.g., Figure 3 (As shown).

[0102] Here, the four-sided light-transmitting atomic gas cell unit 50 can simultaneously meet the requirements of precise incident and exit of dual laser beams in different directions, without the need for additional design of complex optical path turning structures to adapt to the dual-light system, thus adapting to the requirements of optical path flexibility and stability of the dual-light scheme.

[0103] In some specific embodiments, according to the cutting mark C, the area where a single gas chamber 40 is located can be cut as a cutting unit to obtain multiple atomic gas chamber units 50 with four light-transmitting surfaces.

[0104] In some embodiments, the first silicon wafer 20 has a first size, the second silicon wafer 30 has a second size, and the glass wafer 10 has a third size; the third size is equal to the first size and the third size is greater than the second size. By setting the size of the glass wafer 10 to be larger than the size of the second silicon wafer 30, it is beneficial to expose the cutting marks C on the edge of the glass wafer 10, and cutting positioning can be achieved according to the cutting marks C during the cutting process.

[0105] In some embodiments, the specific steps of performing the dicing process may include: using a wafer dicing machine, adjusting the dicing parameters according to the overall bonding thickness, and dicing the atomic gas cells based on the dicing mark C of the glass wafer 10 to divide them into four-sided light-transmitting atomic gas cell units 50.

[0106] In summary, by using the atomic gas cell manufacturing method provided in the embodiments of this application, a long-life atomic gas cell with light passing through all four sides can be prepared.

[0107] Based on this, the present application also provides an atomic gas chamber, which is prepared by the manufacturing method of the atomic gas chamber in any of the above embodiments.

[0108] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0109] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An atomic gas chamber, characterized in that, The atomic gas chamber includes: First silicon wafer; A glass wafer is located on a first silicon wafer. The glass wafer has opposing first and second surfaces, with the first surface located near one end of the first silicon wafer. The first surface of the glass wafer is bonded to the first silicon wafer. The glass wafer has multiple through-hole structures penetrating the first and second surfaces, and these through-hole structures are square-shaped. The through-hole structures and the first silicon wafer form a gas chamber. The sidewall tilt angle of the through-hole structures is less than or equal to 1.5°, and the inner surface roughness of the sidewalls is less than or equal to 80 nm. The glass wafer has dicing marks located on the second surface of the glass wafer, specifically at the edge region of the glass wafer. Based on these dicing marks, the atomic gas chamber is diced to form multiple atomic gas chamber units with four light-transmitting surfaces. These atomic gas chamber units with four light-transmitting surfaces simultaneously satisfy the requirements for dual-beam laser incident and emitted in different directions. Alkali metal, located within the gas chamber; A second silicon wafer is located on the second surface of the glass wafer, the second silicon wafer completely covering the opening of the gas chamber, and the second surface of the glass wafer is bonded to the second silicon wafer; The first silicon wafer has a first size, the second silicon wafer has a second size, and the glass wafer has a third size; the third size is equal to the first size and the third size is greater than the second size.

2. The atomic gas chamber according to claim 1, characterized in that, The atomic gas chamber also includes: A gold structure is located within the gas chamber and on the surface of the first silicon wafer.

3. A method for manufacturing an atomic gas chamber as described in claim 1, characterized in that, The method for manufacturing the atomic gas chamber includes: A glass wafer is provided, the glass wafer having opposing first and second surfaces; A laser process is performed on the glass wafer to form a plurality of through-hole structures penetrating the first surface and the second surface on the glass wafer; The first surface of the glass wafer is bonded to the first silicon wafer, and the through-hole structure and the first silicon wafer form a gas chamber; The gas chamber is filled with an alkali metal; The second surface of the glass wafer is bonded to a second silicon wafer, the second silicon wafer completely covering the opening of the gas chamber.

4. The method for manufacturing an atomic gas chamber according to claim 3, characterized in that, Before bonding the first surface of the glass wafer to the first silicon wafer, the method for manufacturing the atomic gas cell further includes: Provide the first silicon wafer; A gold plating process is performed on the first silicon wafer to form multiple spaced gold structures on the surface of the first silicon wafer.

5. The method for manufacturing an atomic gas chamber according to claim 4, characterized in that, A gold plating process is performed on the first silicon wafer to form a plurality of spaced gold structures on the surface of the first silicon wafer, including: A patterned photoresist layer is formed on the surface of the first silicon wafer; Gold plating material is deposited on the patterned photoresist layer and the surface of the first silicon wafer; The patterned photoresist layer and the gold plating material on the patterned photoresist layer are peeled off to form the gold structure.

6. The method for manufacturing an atomic gas chamber according to claim 5, characterized in that, The patterned photoresist layer is prepared by spin-coating photoresist onto the surface of the first silicon wafer and then exposing and developing it. The gold plating material is prepared by electron beam evaporation process; The patterned photoresist layer and the gold plating material on the patterned photoresist layer are peeled off in an acetone solution by ultrasound.

7. The method for manufacturing an atomic gas chamber according to claim 4, characterized in that, The glass wafer has a first alignment and bonding mark, and the first silicon wafer has a second alignment and bonding mark; Bonding the first surface of the glass wafer to the first silicon wafer includes: bonding the first surface of the glass wafer to the first silicon wafer according to the first alignment bonding mark on the glass wafer and the second alignment bonding mark on the first silicon wafer, wherein the through-hole structure and the first silicon wafer form a gas chamber, and the gold structure is located in the gas chamber.

8. The method for manufacturing an atomic gas chamber according to claim 3, characterized in that, When performing a laser process on the glass wafer to form a plurality of through-hole structures penetrating the first surface and the second surface on the glass wafer, the method for manufacturing the atomic gas cell further includes: forming a cutting mark on the second surface of the glass wafer, the cutting mark being located in the edge region of the glass wafer; After bonding the second surface of the glass wafer to the second silicon wafer, the method for manufacturing the atomic gas cell further includes: performing a cutting process on the atomic gas cell according to the cutting mark to form a plurality of atomic gas cell units with four light-transmitting surfaces.

9. The method for manufacturing an atomic gas chamber according to claim 3, characterized in that, Performing a laser process on the glass wafer includes: performing a water-guided laser process on the glass wafer to form a plurality of through-hole structures penetrating the first surface and the second surface on the glass wafer, wherein the sidewall tilt angle of the through-hole structure is less than or equal to 1.5° and the inner surface roughness of the sidewall is less than or equal to 80 nm.

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