Double-chamber MEMS atomic gas chamber integrating heating and temperature measuring functions and manufacturing method

Abstract

The invention discloses a double-chamber MEMS (Micro Electro Mechanical System) atomic gas chamber integrating heating and temperature measuring functions and a manufacturing method. The double-chamber MEMS atomic gas chamber adopts a glass-silicon-glass bonding three-layer structure, a heating coil and a temperature measuring coil are prepared on the back surface of a top glass cover plate, and a coil electrode is led out from the front surface of the top glass cover plate through a glass through hole technology; an optical cavity and a reaction cavity are arranged on the middle silicon wafer in parallel and are communicated through a micro-channel; the heating coil is made of a transparent conductive material, is located over the optical cavity and can directly heat alkali metal atoms in the cavity, the temperature measuring coil is arranged around the heating coil, and real-time closed-loop control over the temperature of the air chamber can be achieved through a circuit. Compared with an existing integration mode, heat dissipation is reduced, the heating efficiency of the air chamber is improved, and then the sensitivity and stability of quantum precision measurement instruments such as an atomic magnetometer and an atomic clock are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of micro-electromechanical systems, and more specifically, relates to a dual-chamber MEMS atomic gas chamber with integrated heating and temperature measurement functions and a manufacturing method thereof. Background Art

[0002] MEMS atomic gas chambers are key components of quantum precision measuring instruments such as atomic magnetometers and atomic clocks. Their application areas include aeromagnetic surveys, ocean monitoring, geological exploration, earthquake prediction, etc. The performance of MEMS atomic gas chambers directly determines the overall performance of these instruments. In practical applications, the performance of MEMS atomic gas chambers is closely related to their stable working state at a specific temperature. Therefore, precise temperature control becomes its core requirement. At present, electric heating is the main technical means to achieve this temperature control.

[0003] With the rapid development of technology, quantum precision measurement instruments are moving towards miniaturization, which requires quantum sensor devices to further improve in terms of low power consumption, small size, high precision, and tolerance to harsh environments. In this context, the efficient integration of MEMS atomic gas chambers with heating and temperature measurement components has become an important research topic in this field. This integration can not only reduce the overall size of the instrument, but also enhance its performance and stability, thereby better meeting the market demand for portable and precise measurement instruments. Therefore, optimizing the performance of MEMS atomic gas chambers is of great significance to quantum precision measurement.

[0004] The mainstream dual-chamber MEMS atomic gas chamber usually adopts a three-layer structure of glass-silicon-glass. At present, there are two main design schemes for dual-chamber MEMS atomic gas chambers that integrate heating coils and temperature measuring coils: one is to integrate the heating coils and temperature measuring coils directly on the front of the glass cover of the gas chamber, and conduct heat through the glass. Due to the low thermal conductivity of glass (the typical thermal conductivity of JGS1 quartz glass is 1.4W / (m·K)), the heating efficiency is insufficient, and it is difficult to meet the high-precision dynamic temperature control requirements of quantum precision instruments; the other is to integrate the heating coils and temperature measuring coils around the silicon through-hole vias, and conduct heat through the silicon wafer. Due to the high thermal conductivity of the silicon wafer (the typical thermal conductivity of single-crystal silicon is 148W / (m·K)), part of the heat is dissipated outward through the silicon wafer, which also leads to insufficient heating efficiency, restricting the application expansion of dual-chamber MEMS atomic gas chambers in the field of quantum precision measurement. In response to the above problems, the following solutions are proposed. Summary of the invention

[0005] In view of this, the purpose of the present invention is to propose a dual-chamber MEMS atomic gas chamber with integrated heating and temperature measurement functions and a manufacturing method. Through the MEMS process, the heating coil and the temperature measuring coil are integrated on the back of the top glass cover of the dual-chamber MEMS atomic gas chamber. The heating coil is made of transparent conductive material and is located directly above the optical cavity of the dual-chamber MEMS atomic gas chamber. This integration method enables the heating coil to directly heat the alkali metal atoms in the chamber, reduces heat dissipation, and improves heating efficiency, thereby improving the sensitivity and stability of quantum precision measuring instruments such as atomic magnetometers and atomic clocks.

[0006] A dual-chamber MEMS atomic gas chamber with integrated heating and temperature measurement functions comprises a bottom glass cover plate, a silicon wafer and a top glass cover plate bonded in sequence, wherein: The front side of the top glass cover is provided with a metal pad and a lead through hole, the back side of the top glass cover is provided with a heating coil and a temperature measuring coil, and the metal pad is connected to the heating coil and the temperature measuring coil through the lead through hole; The heating coil is a deposited transparent conductive material; The temperature measuring coil is titanium and platinum deposited in sequence; An optical cavity and a reaction cavity are arranged in parallel on the silicon wafer, and the optical cavity and the reaction cavity are connected through a microchannel; An alkali metal releasing agent is placed in the reaction chamber, and the alkali metal releasing agent can release alkali metal atoms when heated to a certain temperature; The bottom glass cover is used to encapsulate the optical cavity.

[0007] According to another aspect of the present invention, a method for preparing a dual-chamber MEMS atomic gas cell with integrated heating and temperature measurement functions is provided, comprising the following steps: S1: Wet-etch the front and back surfaces of the silicon wafer to form an optical cavity and a reaction cavity; S2: deep silicon etching is performed on the front side of the silicon wafer to form a microchannel; S3: Prepare a heating coil and a temperature measuring coil on the back of the top glass cover; S4: Prepare lead through holes and metal pads on the front side of the top glass cover; S5: performing silicon-glass anodic bonding on the silicon wafer and the bottom glass cover to form two layers of prefabricated bonding wafers; S6: filling the reaction cavity of the two-layer prefabricated bonding sheet with an alkali metal release agent, filling with a buffer gas, and performing silicon-glass anodic bonding on the two-layer prefabricated bonding sheet and the top glass cover plate to form a three-layer sealed cavity bonding sheet; S7: cutting the three-layer sealed cavity bonding sheet to obtain a unitized dual-chamber MEMS atomic gas chamber; S8: Use laser to heat the alkali metal releaser in the reaction chamber of the dual-chamber MEMS atomic gas chamber to a certain temperature to release the alkali metal atoms, and test and screen the unitized dual-chamber MEMS atomic gas chamber to obtain a dual-chamber MEMS atomic gas chamber that meets the requirements.

[0008] Step S3 specifically includes: S31: applying glue and performing photolithography on the back of the top glass cover plate, transferring the mask pattern to the back of the top glass cover plate, etching grooves for accommodating the heating coil and the temperature measuring coil on the back of the top glass cover plate by a reactive ion etching process, and removing the glue from the back of the top glass cover plate; S32: applying glue and performing photolithography on the back of the top glass cover plate after the processing in step S31, transferring the mask pattern to the back of the top glass cover plate, depositing a transparent conductive material on the back of the top glass cover plate by magnetron sputtering, removing glue from the back of the top glass cover plate, annealing, and forming a heating coil; S33: Apply glue and perform photolithography on the back of the top glass cover plate after the processing in step S32, transfer the mask pattern to the back of the top glass cover plate, deposit titanium and platinum in sequence on the back of the top glass cover plate by magnetron sputtering, remove the glue from the back of the top glass cover plate, and form a temperature measuring coil.

[0009] Step S4 specifically includes: S41: applying glue and performing photolithography on the front side of the top glass cover plate, transferring the mask pattern to the front side of the top glass cover plate, etching the front side of the top glass cover plate through an inductively coupled plasma etching process, removing the glue from the front side of the top glass cover plate, and forming lead through holes for the heating coil and the temperature measuring coil; S42: Glue and photolithography are performed on the front side of the top glass cover plate after being processed in step S41, and the mask pattern is transferred to the front side of the top glass cover plate. Titanium and gold are sequentially deposited on the front side of the top glass cover plate by magnetron sputtering, and the glue is removed from the front side of the top glass cover plate, and annealing is performed to form a metal pad.

[0010] The beneficial effects of the present invention are as follows: the present invention integrates the heating coil and the temperature measuring coil on the back of the glass cover plate of the dual-chamber MEMS atomic gas chamber through MEMS technology; the heating coil is made of transparent conductive material and is located directly above the optical cavity of the dual-chamber MEMS atomic gas chamber, so that the alkali metal atoms in the chamber can be directly heated, thereby reducing heat dissipation and improving heating efficiency, thereby improving the sensitivity and stability of quantum precision measuring instruments such as atomic magnetometers and atomic clocks. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a schematic diagram of the appearance of an embodiment; Figure 2 Schematic diagram of the structure of the lead through-hole structure, the heating coil and the temperature measuring coil prepared on the front side of the top glass cover plate involved in the embodiment; Figure 3 is a schematic diagram of the structure of the silicon wafer involved in the embodiment; Figure 4 is a cross-sectional schematic diagram of an embodiment; Figure 5 It is the process flow chart of Example 1; Figure 6 It is a process flow chart for preparing a heating coil, a temperature measuring coil, a lead through hole and an Au pad on the surface of the top glass cover plate in Example 1.

[0012] Figure numerals: 11, silicon wafer; 12, optical cavity; 13, reaction cavity; 14, microchannel; 21, top glass cover plate; 22, heating coil; 23, temperature measuring coil; 221, upper heating coil; 222, lower heating coil; 231, upper temperature measuring coil; 232, lower temperature measuring coil; 24, lead through hole; 25, metal pad; 26, insulating layer; 27, metal connection layer; 31, alkali metal releaser; 41, bottom glass cover plate; 51, two-layer prefabricated bonding sheet; 61, three-layer sealed cavity bonding sheet; 71, unitized dual-chamber MEMS atomic gas chamber; 81, buffer gas. DETAILED DESCRIPTION

[0013] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0014] like Figure 1 As shown, the present invention provides a dual-chamber MEMS atomic gas chamber with integrated heating and temperature measurement functions, comprising a bottom glass cover plate 41, a silicon wafer 11 and a top glass cover plate 21 bonded in sequence, wherein a lead through hole 24 and a metal pad 25 are provided on the front side of the top glass cover plate 21, a heating coil 22 and a temperature measuring coil 23 are prepared on the back side of the top glass cover plate 21, and the metal pad 25 is connected to the heating coil 22 and the temperature measuring coil 23 through the lead through hole 24; an optical cavity 12 and a reaction cavity 13 are arranged in parallel on the silicon wafer 11, and the optical cavity 12 and the reaction cavity 13 are connected through a microchannel 14; the bottom glass cover plate 41 is used to encapsulate the optical cavity 12.

[0015] The top glass cover 21 and the bottom glass cover 41 are made of 4-inch Schott BF33 high borosilicate glass with a thickness of 500um; the silicon wafer 11 is made of double-sided polished 4-inch N-type <100> Crystalline silicon wafer, 2mm thick.

[0016] The heating coil 22 is made of transparent conductive material and is located directly above the optical cavity 12, so as to directly heat the alkali metal atoms in the optical cavity 12. The transparent conductive material may be: (1) indium tin oxide (ITO), (2) aluminum-doped zinc oxide (AZO), or (3) graphene.

[0017] The heating coil 22 is a deposited transparent conductive material.

[0018] The temperature measuring coil 23 is titanium and platinum deposited in sequence.

[0019] An alkali metal releasing agent 31 is placed in the reaction chamber 13. The alkali metal releasing agent 31 can release alkali metal atoms when heated to a certain temperature. The alkali metal releasing agent 31 can be: (1) X 2 CrO 4 / Al / Zr mixture, or (2) XN 3 (Azide X), or (3) BaN 6 A mixed solution of XCl and XCl, the above three chemicals used as alkali metal releasers, wherein X represents an alkali metal, generally Rb or Cs.

[0020] In a preferred embodiment of the present invention, the above-mentioned dual-chamber MEMS atomic gas chamber is only one unit. In actual processing, a plurality of array-arranged dual-chamber MEMS atomic gas chamber units are prepared at the same time and then cut. In this way, batch processing operations can be carried out to improve production efficiency.

[0021] Example In this embodiment, the dual-chamber MEMS atomic gas chamber includes an optical cavity 12 and a reaction cavity 13 prepared on the surface of the silicon wafer 11, a microchannel 14 prepared on the front of the silicon wafer 11, a heating coil 22 and a temperature measuring coil 23 prepared on the back of the top glass cover plate 21, a lead through hole 24 and a metal pad 25 prepared on the front of the top glass cover plate 21, and an alkali metal releaser 31 filled in the reaction cavity 13. Through the first anodic bonding, the silicon wafer 11 and the bottom glass cover plate 41 form a two-layer prefabricated bonding sheet 51, and after the alkali metal releaser 31 is filled in the reaction cavity 13, a second anodic bonding is performed, and the two-layer prefabricated bonding sheet 51 and the top glass cover plate 21 form a three-layer sealed cavity bonding sheet 61, and the three-layer sealed cavity bonding sheet 61 includes a plurality of dual-chamber MEMS atomic gas chambers, and a unitized dual-chamber MEMS atomic gas chamber 71 is obtained after cutting.

[0022] A dual-chamber MEMS atomic gas chamber with integrated heating and temperature measurement functions was prepared in a Class 100 clean laboratory. The production method is as follows: S1: wet-etching the front and back surfaces of the silicon wafer 11 to form an optical cavity 12 and a reaction cavity 13; S2: performing deep silicon etching on the front side of the silicon wafer 11 to form a microchannel 14; S3: Prepare a heating coil 22 and a temperature measuring coil 23 on the back of the top glass cover plate 21; S4: preparing lead through holes 24 and metal pads 25 on the front side of the top glass cover plate 21; S5: performing silicon-glass anodic bonding on the silicon wafer 11 and the bottom glass cover plate 41 to form two layers of prefabricated bonding wafers 51; S6: filling the alkali metal release agent 31 into the reaction chamber 13 of the two-layer prefabricated bonding sheet 51, filling with the buffer gas 81, performing silicon-glass anodic bonding on the two-layer prefabricated bonding sheet 51 and the top glass cover plate 21, and forming a three-layer sealed cavity bonding sheet 61; S7: cutting the three-layer sealed cavity bonding sheet 61 to obtain a unitized dual-chamber MEMS atomic gas chamber 71; S8: Use laser to heat the alkali metal releaser 31 in the dual-chamber MEMS atomic gas chamber reaction chamber 13 to a certain temperature to release alkali metal atoms, and test and screen the unitized dual-chamber MEMS atomic gas chamber 71.

[0023] The specific steps of making the unitized dual-chamber MEMS atomic gas cell 71 are described in detail below: Based on the wet etching of the front and back surfaces of the silicon wafer 11 in step S1, the general steps of preparing the optical cavity 12 and the reaction cavity 13 by wet etching are explained. The process flow is as follows: Figure 5 As shown in af: (1) If Figure 5 As shown in a, the silicon wafer 11 is ultrasonically cleaned with an acetone+isopropanol solution, the surface of the silicon wafer 11 is rinsed with deionized water, and blown dry with a nitrogen gun, and a layer of silicon nitride is deposited on the front and back of the silicon wafer 11 by a low-pressure chemical vapor deposition process as a wet etching mask layer with a thickness of 500 nm; (2) If Figure 5 As shown in b, a layer of photoresist is coated on the front and back sides of the silicon wafer 11 by a spin coating process, and the mask pattern is transferred to the front and back sides of the silicon wafer 11 by photolithography; (3) If Figure 5 As shown in c, a reactive ion etching process is used to remove the silicon nitride layer at the photolithography pattern to form a window; (4) If Figure 5 As shown in d, the silicon wafer 11 is ultrasonically cleaned in an acetone solution to remove the photoresist, and then rinsed with deionized water and dried with a nitrogen gun; (5) If Figure 5As shown in e, the surface of the silicon wafer 11 at the window is corroded by wet etching, 30wt% KOH is used as the etching solution, the etching temperature is set to 80°C, the etching rate is 1.4um / min, and the optical cavity 12 and the reaction cavity 13 of the gas chamber are formed. The alkali metal release agent to be filled later has a height of 0.6-0.8mm and a diameter of 1mm. After etching, the reaction cavity 13 is a non-penetrating cavity with a depth of 1mm. The window width is 2mm, which is larger than the height and diameter of the alkali metal release agent. The optical cavity 12 is a penetrating cavity with a depth of 2mm. (6) If Figure 5 As shown in f, the silicon wafer 11 is immersed in a hydrofluoric acid solution to remove the silicon nitride layer.

[0024] Based on deep silicon etching on the front side of the silicon wafer 11 in step S2, the general steps of deep silicon etching to prepare the microchannel 14 are explained. The process flow is as follows: Figure 5 As shown in gi: (1) If Figure 5 As shown in g, a layer of photoresist is coated on the front side of the silicon wafer 11 by using a spraying process, and the mask pattern is transferred to the front side of the silicon wafer 11 by photolithography; (2) If Figure 5 As shown in h, a microchannel 14 connecting the optical cavity 12 and the reaction cavity 13 is formed by a deep silicon etching process; (3) If Figure 5 As shown in Fig. 1, the silicon wafer 11 is ultrasonically cleaned in an acetone solution to remove the photoresist, and then rinsed with deionized water and dried with a nitrogen gun.

[0025] Based on step S3, the general steps of preparing the heating coil 22 and the temperature measuring coil 23 on the back of the top glass cover plate 21 are explained. The process flow is as follows: Figure 6 As shown in ag: S31: Figure 6 As shown in a in FIG. 1 , a groove for accommodating the heating coil 22 and the temperature measuring coil 23 is etched on the back of the top glass cover plate 21: (1) coating a layer of photoresist on the back of the top glass cover plate 21 by a spin coating process, and transferring the mask pattern to the back of the top glass cover plate 21 by photolithography; (2) A groove for accommodating the heating coil 22 and the temperature measuring coil 23 is etched by a reactive ion etching process, and the depth of the groove is 800 nm; (3) ultrasonically cleaning the top glass cover plate 21 in an acetone solution to remove the photoresist, rinsing with deionized water, and drying with a nitrogen gun; S32: Figure 6As shown in b, an upper heating coil 221 is prepared on the back of the top glass cover plate 21: (1) a layer of photoresist is coated on the back of the top glass cover plate 21 by a spin coating process, and a mask pattern is transferred to the back of the top glass cover plate 21 by photolithography; (2) A groove for accommodating the upper heating coil 221 is etched by a reactive ion etching process, and the depth of the groove is 360 nm; (3) depositing 360 nm of indium tin oxide on the back of the top glass cover plate 21 by magnetron sputtering; (4) ultrasonically cleaning the top glass cover plate 21 in an acetone solution to remove the photoresist, and then transferring the top glass cover plate 21 to an isopropanol solution for rinsing and drying with a nitrogen gun; (5) Annealing at 300 °C for 0.5 h in air atmosphere; S33: Figure 6 As shown in c, an upper temperature measuring coil 231 is prepared on the back of the top glass cover plate 21 after being processed in step S32: (1) coating a layer of photoresist on the back of the top glass cover plate 21 by a spin coating process, and transferring the mask pattern to the back of the top glass cover plate 21 by photolithography; (2) A groove for accommodating the upper temperature measuring coil 231 is etched by a reactive ion etching process, and the depth of the groove is 230 nm; (3) depositing 20 nm titanium and 210 nm platinum on the back of the top glass cover plate 21 in sequence by magnetron sputtering; (4) ultrasonically cleaning the top glass cover plate 21 in an acetone solution to remove the photoresist, and then transferring the top glass cover plate 21 to an isopropanol solution for rinsing and drying with a nitrogen gun; S34: Figure 6 As shown in d in FIG. 1 , an insulating layer 26 of upper and lower coils is prepared on the back of the top glass cover plate 21 after being processed in step S33: (1) coating a layer of photoresist on the back of the top glass cover plate 21 by a spin coating process, and transferring the mask pattern to the back of the top glass cover plate 21 by photolithography; (2) Using a plasma enhanced chemical vapor deposition process, 400 nm silicon oxide is deposited on the back of the top glass cover plate 21 as the insulating layer 26 of the upper and lower coils; (3) ultrasonically cleaning the top glass cover plate 21 in an acetone solution to remove the photoresist, rinsing with deionized water, and drying with a nitrogen gun; S35: Figure 6 As shown in e in FIG. 1 , a metal connection layer 27 between the upper and lower coils is prepared on the back of the top glass cover plate 21 after being processed in step S34: (1) coating a layer of photoresist on the back of the top glass cover plate 21 by a spin coating process, and transferring the mask pattern to the back of the top glass cover plate 21 by photolithography; (2) A dielectric film window is opened on the back of the top glass cover plate 21 by reactive ion etching process, with an etching depth of 400 nm; (3) Using magnetron sputtering, 20 nm titanium, 360 nm gold, and 20 nm titanium are sequentially deposited on the back of the top glass cover plate 21; (4) ultrasonically cleaning the top glass cover plate 21 in an acetone solution to remove the photoresist, and then transferring the top glass cover plate 21 to an isopropanol solution for rinsing and drying with a nitrogen gun; (5) Annealing at 300 °C for 0.5 h in a nitrogen atmosphere; S36: Figure 6 As shown in f, a lower heating coil 222 is prepared on the back of the top glass cover plate 21 after being processed in step S35: (1) coating a layer of photoresist on the back of the top glass cover plate 21 by a spin coating process, and transferring the mask pattern to the back of the top glass cover plate 21 by photolithography; (2) depositing 360 nm of indium tin oxide on the back of the top glass cover plate 21 by magnetron sputtering; (3) ultrasonically cleaning the top glass cover plate 21 in an acetone solution to remove the photoresist, and then transferring the top glass cover plate 21 to an isopropanol solution for rinsing and drying with a nitrogen gun; (4) Annealing at 300 °C for 0.5 h in air atmosphere; S37: Figure 6 As shown in g in FIG. 1 , a lower temperature measuring coil 232 is prepared on the back of the top glass cover plate 21 after being processed in step S36: (1) coating a layer of photoresist on the back of the top glass cover plate 21 by a spin coating process, and transferring the mask pattern to the back of the top glass cover plate 21 by photolithography; (2) depositing 20 nm titanium and 210 nm platinum on the back of the top glass cover plate 21 in sequence by magnetron sputtering; (3) The top glass cover plate 21 is ultrasonically cleaned in an acetone solution to remove the photoresist, and then the top glass cover plate 21 is transferred to an isopropanol solution for rinsing and blown dry using a nitrogen gun.

[0026] Based on step S4, the general steps of preparing the lead through hole 24 and the metal pad 25 on the front side of the top glass cover plate 21 are explained. The process flow is as follows: Figure 6 As shown in hi: S41: Figure 6 As shown in h in FIG. 1 , a lead through hole 24 is prepared on the front side of the top glass cover plate 21: (1) coating a layer of photoresist on the front surface of the top glass cover plate 21 by a spin coating process, and transferring the mask pattern to the front surface of the top glass cover plate 21 by photolithography; (2) By using an inductively coupled plasma etching process, lead holes 24 for the heating coil 22 and the temperature measuring coil 23 are etched on the front surface of the top glass cover plate 21, with an etching depth of 500 um; (3) ultrasonically cleaning the top glass cover plate 21 in an acetone solution to remove the photoresist, rinsing with deionized water, and drying with a nitrogen gun; S42: Figure 6 As shown, a metal pad 25 is prepared on the front side of the top glass cover plate 21 after being processed in step S41: (1) coating a layer of photoresist on the front surface of the top glass cover plate 21 by a spin coating process, and transferring the mask pattern to the front surface of the top glass cover plate 21 by photolithography; (2) Depositing 20 nm titanium and 100 nm gold on the front surface of the top glass cover plate 21 in sequence by magnetron sputtering; (3) ultrasonically cleaning the top glass cover plate 21 in an acetone solution to remove the photoresist, and then transferring the top glass cover plate 21 to an isopropanol solution for rinsing and drying with a nitrogen gun; (4) Anneal at 300°C in a nitrogen atmosphere for 0.5 h.

[0027] Based on step S5, the general steps of preparing the two-layer prefabricated bonding sheet 51 are explained as follows: Figure 5 As shown in FIG. 1 , the silicon wafer 11 and the bottom glass cover plate 41 are mounted on the bonding tray through optical alignment, and are sent into the bonding chamber to perform the anodic bonding procedure to form two layers of prefabricated bonding wafers 51. The silicon wafer 11 is connected to the anode, and the bottom glass cover plate 41 is connected to the cathode. The top hot plate and the bottom hot plate of the bonding machine are heated to 120°C, and the bonding chamber inside the bonding machine is evacuated (the vacuum degree is less than 1×10 -5 mbar), the quartz pressure plate inside the bonding machine applies a pressure of 1000N to the bottom glass cover plate 41, and the internal electrode applies a voltage of 1000V to form a two-layer prefabricated bonding sheet 51, and the bonding surfaces are the back side of the silicon wafer 11 and the front side of the bottom glass cover plate 41.

[0028] Based on step S6, the general steps of preparing the three-layer sealed cavity bonding sheet 61 are explained: Figure 5 As shown in Figure 1, the two prefabricated bonding sheets 51 and the top glass cover plate 21 are mounted on the bonding tray of the bonding machine by optical alignment, and then the alkali metal release agent 31 is filled into the reaction chamber 13. A gap is formed between the two prefabricated bonding sheets 51 and the top glass cover plate 21 by using the thick gasket on the bonding tray, so that the buffer gas 81 can enter the optical cavity 12 and the reaction chamber 13. The top hot plate and the bottom hot plate of the bonding machine are heated to 120°C, and the bonding chamber inside the bonding machine is evacuated (the vacuum degree is less than 1×10-5 mbar) and keep the vacuum for 30 minutes, then fill with argon as buffer gas 81, and keep it for a while to allow the argon to diffuse into the optical cavity 12 and the reaction cavity 13. The quartz pressure plate inside the bonding machine applies a pressure of 1000N to the top glass cover plate 21, and the internal electrode applies a voltage of 1000V to form a three-layer sealed cavity bonding sheet 61, with the bonding surfaces being the front side of the silicon wafer 11 and the back side of the top glass cover plate 21.

[0029] In step S6, an alkali metal releasing agent 31 is filled into the reaction chamber 13 of the two-layer prefabricated bonding sheet 51, wherein the alkali metal releasing agent 31 can release alkali metal atoms when heated to a certain temperature. The following three types of chemicals are commonly used as the alkali metal releasing agent 31: (1) X 2 CrO 4 / Al / Zr mixture, or (2) XN 3 (Azide X), or (3) BaN 6 A mixed solution of 2,4-dichloro-2-nitrogen and 2,4-dichloro-2-nitrogen, wherein X represents an alkali metal, generally Rb or Cs.

[0030] In step S7 , the three-layer sealed cavity bonding sheet 61 is cut to obtain a unitized dual-chamber MEMS atomic gas cell 71 . The three-layer sealed cavity bonding sheet 61 is generally cut using a wafer dicing machine or a laser.

[0031] In step S8, the alkali metal release agent 31 in the reaction chamber 13 of the dual-chamber MEMS atomic gas chamber 71 is heated to a certain temperature by laser to release alkali metal atoms. The laser is focused by a lens, and the beam diameter is less than 1 mm, which can heat the alkali metal release agent to above 500° C. The unitized dual-chamber MEMS atomic gas chamber 71 is tested and screened to obtain a dual-chamber MEMS atomic gas chamber 71 with performance that meets the standard.

[0032] In the above embodiment, the basic method for testing and screening the unitized dual-chamber MEMS atomic gas chamber 71 is to build an optical platform to obtain the absorption spectrum of the dual-chamber MEMS atomic gas chamber 71 corresponding to the alkali metal atoms, such as using an 894nm laser to test the absorption spectrum corresponding to the Cs atom. Furthermore, the present invention directly heats the alkali metal atoms in the optical cavity 12 of the dual-chamber MEMS atomic gas chamber 71 through the heating coil 22, and at the same time obtains the absorption spectrum of the alkali metal atoms in the dual-chamber MEMS atomic gas chamber 71 through laser pumping. Furthermore, the heating coil 22 and the temperature measuring coil 23 can be connected to the controller to form a PID closed-loop control, so that under the action of the heating coil 22 and the temperature measuring coil 23, the heating temperature of the gas chamber is consistent with the desired heating temperature.

[0033] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A dual-chamber MEMS atomic gas chamber with integrated heating and temperature measurement functions, comprising a bottom glass cover plate (41), a silicon wafer (11) and a top glass cover plate (21) bonded in sequence, characterized in that The front side of the top glass cover plate (21) is provided with a lead through hole (24) and a metal pad (25), and the back side of the top glass cover plate (21) is provided with a heating coil (22) and a temperature measuring coil (23), and the metal pad (25) is connected to the heating coil (22) and the temperature measuring coil (23) through the lead through hole (24).

2. A dual-chamber MEMS atomic gas chamber with integrated heating and temperature measurement functions according to claim 1, characterized in that The heating coil (22) is made of a transparent conductive material, an optical cavity (12) is provided on the silicon wafer (11), and the heating coil (22) is located directly above the optical cavity (12) to directly heat the alkali metal atoms in the optical cavity (12).

3. A dual-chamber MEMS atomic gas chamber with integrated heating and temperature measurement functions according to claim 1, characterized in that The temperature measuring coil (23) is made of metal platinum, and the temperature measuring coil (23) is distributed around the heating coil (22).

4. A method for preparing a dual-chamber MEMS atomic gas chamber with integrated heating and temperature measurement functions, characterized in that , including the following steps: S1: performing wet etching on the front and back surfaces of a silicon wafer (11) to form an optical cavity (12) and a reaction cavity (13); S2: performing deep silicon etching on the front side of the silicon wafer (11) to form a microchannel (14); S3: preparing a heating coil (22) and a temperature measuring coil (23) on the back of the top glass cover plate (21); S4: preparing lead through holes (24) and metal pads (25) on the front side of the top glass cover plate (21); S5: performing silicon-glass anodic bonding on the silicon wafer (11) and the bottom glass cover plate (41) to form two layers of prefabricated bonding wafers (51); S6: filling the reaction chamber (13) of the two-layer prefabricated bonding sheet (51) with an alkali metal release agent (31), filling with a buffer gas (81), and performing silicon-glass anodic bonding on the two-layer prefabricated bonding sheet (51) and the top glass cover plate (21) to form a three-layer sealed chamber bonding sheet (61); S7: cutting the three-layer sealed cavity bonding sheet (61) to obtain a unitized dual-chamber MEMS atomic gas chamber (71); S8: Using a laser to heat the alkali metal releaser (31) in the reaction chamber (13) of the dual-chamber MEMS atomic gas chamber (71) to a certain temperature to release the alkali metal atoms, and testing and screening the unitized dual-chamber MEMS atomic gas chamber (71) to obtain a dual-chamber MEMS atomic gas chamber (71) that meets the requirements.

5. The method for preparing a dual-chamber MEMS atomic gas cell with integrated heating and temperature measurement functions according to claim 4, characterized in that: Step S3 specifically includes: S31: applying glue and performing photolithography on the back of the top glass cover plate (21), transferring the mask pattern to the back of the top glass cover plate (21), etching a groove for accommodating the heating coil (22) and the temperature measuring coil (23) on the back of the top glass cover plate (21) by a reactive ion etching process, and removing the glue from the back of the top glass cover plate (21); S32: applying glue and performing photolithography on the back of the top glass cover plate (21) after being processed in step S31, transferring the mask pattern to the back of the top glass cover plate (21), depositing a transparent conductive material on the back of the top glass cover plate (21) by magnetron sputtering, removing glue from the back of the top glass cover plate (21), and annealing to form a heating coil (22); S33: Glue coating and photolithography are performed on the back of the top glass cover plate (21) after being processed in step S32, and the mask pattern is transferred to the back of the top glass cover plate (21). Titanium and platinum are sequentially deposited on the back of the top glass cover plate (21) by magnetron sputtering, and the glue is removed from the back of the top glass cover plate (21) to form a temperature measuring coil (23).

6. The method for preparing a dual-chamber MEMS atomic gas cell with integrated heating and temperature measurement functions according to claim 4, characterized in that: Step S4 specifically includes: S41: applying glue and performing photolithography on the front side of the top glass cover plate (21), transferring the mask pattern to the front side of the top glass cover plate (21), etching a lead through hole (24) on the front side of the top glass cover plate (21) by an inductively coupled plasma etching process, and removing the glue from the front side of the top glass cover plate (21); S42: Glue coating and photolithography are performed on the front side of the top glass cover plate (21) after being processed in step S41, and the mask pattern is transferred to the front side of the top glass cover plate (21). Titanium and gold are sequentially deposited on the front side of the top glass cover plate (21) by magnetron sputtering, and the glue is removed from the front side of the top glass cover plate (21), followed by annealing to form a metal pad (25).

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