Method and device for preparing wafer-level alkali metal gas chamber

Abstract

The present invention relates to a method and device for preparing a wafer-level alkali metal gas chamber. The method comprises preparing a pre-gas chamber wafer unit, depositing an alkali metal in a corresponding gas chamber hole groove, and after depositing the required alkali metal in the gas chamber hole groove, cooling the pre-gas chamber wafer unit to room temperature; providing a gas chamber packaging wafer, and performing low-temperature pre-bonding on the gas chamber packaging wafer and the pre-gas chamber wafer unit cooled to room temperature, so that after the low-temperature pre-bonding, the gas chamber hole groove in the pre-gas chamber wafer unit is sealed with the gas chamber packaging wafer; performing high-temperature anodic bonding on the low-temperature bonded gas chamber packaging wafer and the pre-gas chamber wafer unit, wherein, during the high-temperature anodic bonding, the bonding gas pressure is in the background vacuum state of the molecular pump. The present invention can effectively realize the preparation of the alkali metal gas chamber, avoid the escape of the alkali metal due to high temperature, and at the same time ensure the bonding strength and improve the reliability of the prepared alkali metal gas chamber.

Description

Technical Field

[0001] The present invention relates to a preparation method and a device, in particular to a preparation method and a device for a wafer-level alkali metal gas chamber. Background Art

[0002] Alkali metal vapor cells are core components of quantum instruments such as atomic clocks, atomic magnetometers, and atomic gyroscopes, and their quality directly determines device performance. With the advancement of modern technology and the increasing demand for device miniaturization, low power consumption, and high integration, the fabrication of miniaturized alkali metal vapor cells has become a hot topic in scientific and technological research worldwide.

[0003] Traditional alkali metal gas cells mostly adopt glass bubble type, but glass bubble type alkali metal gas cells have defects such as difficulty in precise control of the gas cell shape and inability to achieve mass production. However, the application of MEMS technology to realize the preparation of wafer-level alkali metal gas cells has become possible.

[0004] At present, the mainstream technology for preparing alkali metal gas chambers abroad is: making through holes on silicon wafers through KOH corrosion or deep reactive ion etching process, and performing an anodic bonding after the preparation, then adding alkali metal, and finally performing a second anodic bonding in a high vacuum or buffer gas environment to complete the gas chamber sealing.

[0005] While the micromachining process for creating the gas chamber cavity is mature, achieving alkali metal deposition and gas chamber encapsulation are two key steps. Due to the chemical properties of alkali metals, which are reactive and easily react with water and oxygen, the preparation process for filling the gas chamber with alkali metal requires a platform that is easily accessible to human operators and the necessary inert gas atmosphere. However, conventional anodic bonding equipment and processes are inconvenient and expensive.

[0006] Due to the low melting point and easy vaporization of alkali metals, the alkali metal in the gas chamber groove is easily thermally released during the anodic bonding process. This results in insufficient alkali metal atoms within the gas chamber cavity, leading to poor performance and a shortened lifespan of the alkali metal gas chamber. Furthermore, alkali metal oxidation and poor uniformity make process conditions difficult to control, making it impossible to meet the industrial production needs of alkali metal gas chambers. Summary of the Invention

[0007] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a method and device for preparing a wafer-level alkali metal gas chamber, which can effectively realize the preparation of the alkali metal gas chamber, avoid the escape of the alkali metal due to high temperature, and at the same time ensure the bonding strength and improve the reliability of the prepared alkali metal gas chamber.

[0008] According to the technical solution provided by the present invention, a method for preparing a wafer-level alkali metal gas chamber comprises:

[0009] preparing a pre-gas chamber wafer unit, wherein the pre-gas chamber wafer unit comprises a plurality of gas chamber holes for receiving alkali metals;

[0010] Aligning the pre-gas chamber wafer unit prepared above with an alkali metal evaporation device for generating alkali metal vapor, wherein the alkali metal evaporation device includes an alkali metal reaction pool having a plurality of reaction pool slots, and aligning the gas chamber slots in the pre-gas chamber wafer unit with the reaction pool slots of the alkali metal reaction pool one by one, so that each gas chamber slot and the corresponding reaction pool slot form an alkali metal feeding channel;

[0011] The alkali metal material pre-placed in the reaction tank is heated and evaporated, and after the heating and evaporation, the alkali metal is deposited in the corresponding gas chamber hole groove using the above-mentioned alkali metal donation channel. After the required alkali metal is deposited in the gas chamber hole groove, the pre-gas chamber wafer unit is cooled to room temperature;

[0012] Providing a gas chamber packaging wafer, and performing low-temperature pre-bonding on the gas chamber packaging wafer and the pre-gas chamber wafer unit cooled to room temperature, so that after the low-temperature pre-bonding, the gas chamber holes in the pre-gas chamber wafer unit are sealed with the gas chamber packaging wafer;

[0013] The low-temperature bonded gas chamber packaging wafer and the pre-gas chamber wafer unit are subjected to high-temperature anodic bonding, wherein during the high-temperature anodic bonding, the bonding gas pressure is in a molecular pump background vacuum state.

[0014] The pre-gas chamber wafer unit includes a gas chamber main wafer and a gas chamber auxiliary wafer bonded and fixed to one surface of the gas chamber main wafer, wherein:

[0015] The air chamber hole groove penetrates the air chamber main wafer, and the air chamber auxiliary wafer is used to close a notch of the air chamber hole groove;

[0016] When the air chamber packaging wafer is pre-bonded with the pre-air chamber wafer unit, the air chamber packaging wafer is bonded and fixed to the other surface of the air chamber main wafer, so that all the air chamber holes in the air chamber main wafer are sealed by the air chamber packaging wafer and the air chamber auxiliary wafer.

[0017] The gas chamber main wafer includes a silicon wafer, and the gas chamber auxiliary wafer and the gas chamber packaging wafer both include glass wafers;

[0018] The bonding and fixing method of the gas chamber auxiliary wafer and the gas chamber main wafer includes anodic bonding.

[0019] The gas chamber main wafer also includes an alkali metal positioning channel, wherein the alkali metal positioning channel passes through the gas chamber main wafer;

[0020] The alkali metal evaporation device includes a plurality of positioning pins that can extend into the alkali metal positioning channel, a hot plate for providing a heat source, and a cold plate for providing a cold source, wherein:

[0021] The positioning pins are arranged on the alkali metal reaction tank, and the positioning pins and the alkali metal are aligned and connected with the positioning channel to ensure that the pre-gas chamber wafer unit is aligned with the alkali metal reaction tank.

[0022] A hot stage is used to provide a heat source for evaporation of alkali metal substances in the alkali metal reaction pool, and a cold plate is used to cool the alkali metal entering the gas chamber pores and grooves, so that the alkali metal is deposited in the gas chamber pores and grooves.

[0023] A low-temperature pre-bonding is performed using an anodic bonding machine. During the low-temperature pre-bonding, the gas chamber package wafer is located on the pre-gas chamber wafer unit;

[0024] During low-temperature pre-bonding, the temperature of the bonding head of the anodic bonding equipment is 150°C to 350°C, and the anodic bonding chamber is in a high vacuum state or filled with buffer gas pressure;

[0025] During pre-bonding, the bonding pressure is 0.2MPa~0.4MPa, and the working voltage of the anodic bonding machine is 0V~300V, so that the bonding interface between the gas chamber packaged wafer and the pre-gas chamber wafer unit is pre-bonded, and after the pre-bonding is generated at the bonding interface, the pre-bonding state is stopped.

[0026] High temperature anodic bonding is performed using an anodic bonding machine, wherein:

[0027] During high-temperature anodic bonding, the operating voltage of the anodic bonding machine is 800V to 1000V, and the temperature of the bonding head is 320°C to 350°C.

[0028] After high-temperature anodic bonding, when the temperature of the bonding head of the anodic bonding machine drops to 150°C to 200°C, the pressure of the bonding head is removed and the vacuum of the anodic bonding chamber is broken to obtain an air chamber wafer packaging unit;

[0029] The gas chamber wafer packaging unit is cut to obtain a single-cavity alkali metal gas chamber formed by a gas chamber hole groove.

[0030] Before the pre-gas chamber wafer unit is aligned with the alkali metal evaporation device, the pre-gas chamber wafer unit is first vacuumed and heated to remove moisture, and

[0031] Before the air chamber packaging wafer is pre-bonded with the pre-air chamber wafer unit at low temperature, the air chamber packaging wafer is subjected to a vacuum heating and dehumidification treatment.

[0032] The alkali metal substances pre-placed in the alkali metal reaction tank include alkali metal droplets and / or alkali metal alloys.

[0033] A wafer-level alkali metal gas chamber device is prepared using the above-mentioned preparation method.

[0034] The present invention has the advantage that when alkali metal deposits are formed in the gas chamber apertures, i.e., during the thermal evaporation of the alkali metal material, the surface of the gas chamber main wafer in the pre-gas chamber wafer unit is not contaminated by the alkali metal, thereby improving the success rate of the pre-gas chamber wafer unit in the subsequent anodic bonding packaging process. Furthermore, alkali metal deposits can be simultaneously obtained in multiple gas chamber apertures, thereby improving preparation efficiency.

[0035] When the gas chamber packaged wafer is bonded to the pre-gas chamber wafer unit, the gas chamber holes of the pre-gas chamber wafer unit are first sealed by pre-bonding in a low pressure or vacuum environment and at a low bonding temperature. Then, the pre-gas chamber wafer unit is heated to a high temperature in the background vacuum environment of the bonding chamber for a second anodic bonding. This solves the problem of alkali metal easily escaping due to heat, ensures the performance of the formed alkali metal gas chamber, and at the same time, guarantees the requirements of bonding air tightness and bonding strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figures 1 to 6 This is a cross-sectional view of the specific implementation steps of a preparation process of a wafer-level alkali metal gas chamber of the present invention, wherein:

[0037] Figure 1 This is a cross-sectional view of the gas chamber main wafer mask window prepared by the present invention.

[0038] Figure 2 This is a cross-sectional view of the present invention after the air chamber holes and alkali metal positioning channels are prepared in the air chamber main wafer.

[0039] Figure 3 This is a cross-sectional view of the present invention after removing the gas chamber main wafer mask.

[0040] Figure 4 This is a cross-sectional view of the present invention after bonding with the gas chamber auxiliary wafer to form a pre-gas chamber wafer unit.

[0041] Figure 5 This is a cross-sectional view of the present invention after alkali metal is deposited in the gas chamber groove.

[0042] Figure 6 This is a cross-sectional view of the gas chamber packaging wafer and the gas chamber main wafer after bonding.

[0043] Figure 7 This is an embodiment of the alkali metal evaporation device of the present invention when performing alkali metal deposition.

[0044] Figure 8 This is an embodiment of the present invention when an anodic bonding machine is used for anodic bonding.

[0045] Explanation of the accompanying drawings: 1-gas chamber main wafer, 2-gas chamber main wafer mask, 3-gas chamber main wafer mask window, 4-gas chamber hole groove, 5-alkali metal positioning channel, 6-gas chamber auxiliary wafer, 7-deposited alkali metal, 8-gas chamber packaging wafer, 9-alkali metal gas chamber, 10-hot stage, 11-alkali metal reaction pool, 12-positioning column, 13-channel plate, 14-cold plate, 15-channel plate hole, 16-reaction pool groove, 17-alkali metal substance, 18-lower bonding head, 19-upper bonding head and 20-bonding fixture. DETAILED DESCRIPTION

[0046] The present invention will be further described below with reference to specific drawings and embodiments.

[0047] In order to effectively prepare an alkali metal gas cell, avoid the escape of alkali metal due to high temperature, ensure the bonding strength, and improve the reliability of the prepared alkali metal gas cell, a method for preparing a wafer-level alkali metal gas cell is provided. In one embodiment of the present invention, the method comprises:

[0048] Prepare a pre-gas chamber wafer unit, wherein the pre-gas chamber wafer unit includes a plurality of gas chamber holes 4 for receiving alkali metals;

[0049] The pre-gas chamber wafer unit prepared above is aligned with an alkali metal evaporation device for generating alkali metal vapor, wherein the alkali metal evaporation device includes an alkali metal reaction pool 11 having a plurality of reaction pool slots 16, and the gas chamber slots 4 in the pre-gas chamber wafer unit are aligned one by one with the reaction pool slots 16 of the alkali metal reaction pool 11, so that each gas chamber slot 4 and the corresponding reaction pool slot 16 form an alkali metal feeding channel;

[0050] The alkali metal material pre-placed in the reaction tank 16 is heated and evaporated. After the heating and evaporation, the alkali metal is deposited in the corresponding gas chamber hole groove 4 using the above-mentioned alkali metal donation channel. After the desired alkali metal is deposited in the gas chamber hole groove 4, the pre-gas chamber wafer unit is cooled to room temperature.

[0051] Providing a gas chamber packaging wafer 8, and performing low-temperature pre-bonding on the gas chamber packaging wafer 8 and the pre-gas chamber wafer unit cooled to room temperature, so that after the low-temperature pre-bonding, the gas chamber hole groove 4 in the pre-gas chamber wafer unit is sealed by the gas chamber packaging wafer 8;

[0052] The low-temperature bonded gas chamber packaging wafer 8 and the pre-gas chamber wafer unit are subjected to high-temperature anodic bonding. During the high-temperature anodic bonding, the bonding gas pressure is in the background vacuum state of the molecular pump.

[0053] Figure 4An embodiment of preparing a pre-gas chamber wafer unit is shown in FIG. 1 . Specifically, the pre-gas chamber wafer unit includes a gas chamber main wafer 1 and a gas chamber auxiliary wafer 6 bonded and fixed to one surface of the gas chamber main wafer 1, wherein:

[0054] The air chamber hole groove 4 passes through the air chamber main wafer 1, and the air chamber auxiliary wafer 6 is used to close a notch of the air chamber hole groove 4;

[0055] When the air chamber packaging wafer 8 is pre-bonded with the pre-air chamber wafer unit, the air chamber packaging wafer 8 is bonded and fixed to the other surface of the air chamber main wafer 1 so as to use the air chamber packaging wafer 8 and the air chamber auxiliary wafer 6 to seal all the air chamber holes 4 in the air chamber main wafer 1.

[0056] Figures 1 to 4 The specific preparation process of the pre-gas chamber wafer unit in step 4 is shown, specifically:

[0057] Provide a gas chamber main wafer 1, which can generally be a silicon wafer; prepare a gas chamber main wafer mask 2 on one surface of the gas chamber main wafer 1, and pattern the gas chamber main wafer mask 2. The patterned situation is as follows Figure 1 As shown. The gas chamber master wafer mask 2 can generally be photoresist. The method and technical means for patterning the gas chamber master wafer mask 2 can be selected according to needs. After patterning, a plurality of gas chamber master wafer mask windows 3 can be obtained. The gas chamber master wafer mask windows 3 penetrate the gas chamber master wafer mask 2, and the gas chamber master wafer mask windows 3 are used to expose the corresponding surface of the gas chamber master wafer 1.

[0058] The gas chamber main wafer 1 is etched using the gas chamber main wafer mask 2 and the gas chamber main wafer mask window 3 to obtain a plurality of main wafer hole grooves penetrating the gas chamber main wafer 1 after etching, and the main wafer hole grooves are exactly corresponding to the gas chamber main wafer mask window 3. Figure 2 In the figure, the main wafer hole groove includes an air chamber hole groove 4 and an alkali metal positioning channel 5. The inner diameter of the air chamber hole groove 4 is generally larger than the inner diameter of the alkali metal positioning channel 5. The alkali metal positioning channel 5 is located in the outer circle, and the air chamber hole groove 4 is located in the central area of ​​the air chamber main wafer 1.

[0059] After etching the gas chamber main wafer 1, the gas chamber main wafer mask 2 is removed using common technical means in this technical field, such as Figure 3 As shown, Figure 3 In the embodiment, the air chamber hole groove 4 and the alkali metal positioning channel 5 are both open at both ends.

[0060] Provide a gas chamber auxiliary wafer 6, which can generally be a glass wafer, and bond the gas chamber auxiliary wafer 6 to one surface of the gas chamber main wafer 1 by using an anodic bonding method, such as Figure 4After the gas chamber auxiliary wafer 6 is bonded and fixed to the gas chamber main wafer 1, one end of the gas chamber hole groove 4 and the alkali metal positioning channel 5 is opened. At this time, the gas chamber hole groove 4 and the alkali metal positioning channel 5 are both open at one end.

[0061] After preparing the pre-gas chamber wafer unit, it is necessary to deposit the alkali metal in the desired gas chamber hole groove 4. Figure 7 FIG. 3 shows an embodiment of using an alkali metal evaporation device to deposit alkali metal in the gas chamber hole groove 4.

[0062] The alkali metal evaporation device includes at least an alkali metal reaction pool 11 for receiving a pre-set alkali metal substance 17. The alkali metal reaction pool 11 includes a plurality of reaction pool slots 16. The alkali metal reaction pool 11 receives the pre-set alkali metal substances 17, specifically, the pre-set alkali metal substances 17 are respectively received in the reaction pool slots 16. In order to achieve the deposition of alkali metal in the gas chamber hole slot 4, the gas chamber hole slot 4 in the pre-gas chamber wafer unit corresponds to the reaction pool slot 16 one by one, that is, one gas chamber hole slot 4 corresponds to one reaction pool slot 16. Generally, the number of reaction pool slots 16 is consistent with the number of gas chamber hole slots 4, so that one gas chamber hole slot 4 and the corresponding reaction pool slot 16 form an alkali metal feeding channel. Specifically, the formed alkali metal feeding channel is a closed channel, that is, the alkali metal substance 17 pre-set in a reaction pool slot 16 will only enter the corresponding gas chamber hole slot 4 through the alkali metal feeding channel after evaporation, so as to be deposited in the gas chamber hole slot 4 and obtain the deposited alkali metal 7.

[0063] As can be seen from the above description, the gas chamber main wafer 1 further includes an alkali metal positioning channel 5, wherein the alkali metal positioning channel 5 passes through the gas chamber main wafer 1;

[0064] The alkali metal evaporation device includes a plurality of positioning pins 12 that can extend into the alkali metal positioning channel 5, a hot plate 10 for providing a heat source, and a cold plate 14 for a cold source, wherein:

[0065] The positioning pins 12 are provided on the alkali metal reaction tank 11, and the positioning pins 12 are aligned and connected with the alkali metal positioning channel 5 so that the pre-gas chamber wafer unit is aligned with the alkali metal reaction tank 11;

[0066] The hot stage 10 provides a heat source for evaporating the alkali metal substances in the alkali metal reaction pool 11 , and the cold plate 14 cools the alkali metal entering the gas chamber slot 4 so that the alkali metal is deposited in the gas chamber slot 4 .

[0067] To facilitate alignment of the pre-gas chamber wafer unit, symmetrically distributed positioning posts 12 are provided on the alkali metal reaction pool 11. The positioning posts 12 are arranged vertically and are used to align with the alkali metal dosing positioning channels 5 on the gas chamber main wafer 1. A channel plate 13 is placed over the positioning posts 12 to provide spacing between the pre-gas chamber wafer unit and the alkali metal reaction pool 11 and to increase the path of the alkali metal dosing channel.

[0068] Figure 7 In the embodiment, a plurality of channel plate holes 15 are provided in the channel plate 13. The channel plate holes 15 extend through the channel plate 13. When the channel plate 13 is placed on the positioning posts 12, the channel plate holes 15 are aligned with the gas chamber slots 4 and the reaction tank slots 16. In other words, the channel plate holes 15 serve as part of the alkali metal dosing channel. In a specific implementation, the channel plate 13 is supported on the alkali metal reaction tank 11, and the pre-gas chamber wafer unit is supported on the channel plate 13.

[0069] The alkali metal reaction pool 11 is placed on the hot plate 10, and the pre-gas chamber wafer unit is in contact with the cold plate 14. Specifically, the pre-gas chamber wafer unit is in contact with the cold plate 14 via the gas chamber auxiliary wafer 6. The hot plate 10 can heat the alkali metal reaction pool 11, causing the alkali metal substance 17 pre-placed in the reaction pool groove 16 to evaporate. After evaporation, the alkali metal substance 17 enters the corresponding gas chamber slot 4 through the channel plate hole 15. The alkali metal substance 17 entering the gas chamber slot 4 is deposited under the action of the cold plate 14, thereby forming deposited alkali metal 7 in the gas chamber slot 4. The hot plate 10 and the cold plate 14 can adopt existing commonly used forms, specifically based on the requirements of using the hot plate 10 to heat the alkali metal reaction pool 11 and using the cold plate 14 to cool the pre-gas chamber wafer unit.

[0070] As can be seen from the above description, when the alkali metal 7 is deposited in the gas chamber slots 4, that is, during the thermal evaporation of the alkali metal material 17, the surface of the gas chamber main wafer 1 in the pre-gas chamber wafer unit is not contaminated by the alkali metal, thereby improving the success rate of the pre-gas chamber wafer unit in the subsequent anodic bonding packaging process. At the same time, the alkali metal 7 can be deposited simultaneously in multiple gas chamber slots 4, improving the production efficiency.

[0071] In a specific implementation, the alkali metal substance 17 preset in the alkali metal reaction tank 11 includes alkali metal droplets and / or alkali metal alloys.

[0072] The following describes the condition of the pre-placed alkali metal substance 17 and the process of evaporation and deposition in the gas chamber pores 4.

[0073] Example 1

[0074] Use a pipette to draw 38 μL of the barium azide-cesium chloride aqueous solution and drip it into the reaction tank 16 of the alkali metal reaction cell 11. Heat the alkali metal reaction cell 11 to 100°C using the hot plate 10 to dry out the moisture, then heat it to 150°C to remove moisture. Then, evacuate the alkali metal reaction cell 11 and heat it to 180°C to remove moisture. Place the pre-gas chamber wafer unit on the cold plate 14 and cool it to room temperature. Then, align the pre-gas chamber wafer unit with the channel plate 13 and positioning pins 12, stack them, and place them on the alkali metal reaction cell 11. This ensures proper alignment between the pre-gas chamber wafer unit and the alkali metal reaction cell 11. At this point, the cold plate 14 can be removed and temporarily unused.

[0075] The alkali metal reaction pool 11 is heated to 300°C. During the heating process, barium azide decomposes into elemental barium and reduces cesium chloride to generate alkali metal cesium vapor, which moves upward. The alkali metal cesium vapor passes through the channel plate 13 and is deposited in the gas chamber slot 4 at the cold end. After waiting for 4 minutes, the pre-gas chamber wafer unit is removed and placed on the cold plate 14 to cool to room temperature. At this time, the alkali metal 7 is deposited in each gas chamber slot 4.

[0076] Example 2

[0077] Use a micro pipette to suck up cesium metal and drop it into the reaction tank 16 in the alkali metal reaction tank 11 in sequence. Then, align it with the channel plate 13 and the pre-gas chamber wafer unit using the positioning column 12 and stack them on the alkali metal reaction tank 11 in sequence, so that the pre-gas chamber wafer unit is positively aligned with the alkali metal reaction tank 11, and the pre-gas chamber wafer unit is in contact with the cold plate 14.

[0078] The alkali metal reaction pool 11 is heated to 150°C using a hot plate 10, causing the cesium metal in the reaction pool groove 16 to generate alkali metal cesium vapor and move upward. After passing through the channel plate 13, the alkali metal vapor is deposited in the gas chamber slot 4 at the cold end. After waiting for 10 minutes, the pre-gas chamber wafer unit is removed and placed on a cold plate 14 to cool to room temperature. At this time, alkali metal 7 is deposited in each gas chamber slot 4.

[0079] Example 3

[0080] Use tweezers to pick up a single cesium pellet and place it into the reaction tank 16 within the alkali metal reaction cell 11. Vacuum and heat the reaction cell to remove moisture. Once completed, place the pre-gas chamber wafer unit on the cold plate 14 and cool it to room temperature. After cooling to room temperature, align the alkali metal reaction cell 11, the channel plate 13, and the pre-gas chamber wafer unit using the positioning pins 12. These are then stacked and placed in a sequence, achieving positive alignment between the pre-gas chamber wafer unit and the alkali metal reaction cell 11. At this point, the cold plate 14 can be removed and temporarily unused.

[0081] The alkali metal reaction pool 11 is heated to 550°C using a hot plate 10, causing the cesium pellets in the reaction pool slot 16 to decompose and generate alkali metal cesium vapor, which moves upward. The alkali metal vapor passes through the channel plate 13 and is deposited in the gas chamber slot 4 at the cold end. After waiting for a certain period of time, the pre-gas chamber wafer unit is removed and placed on a cold plate 14 to cool to room temperature. At this time, alkali metal 7 is deposited in each gas chamber slot 4.

[0082] Example 4

[0083] Use a pipette to draw 38ul of the barium azide and rubidium chloride aqueous solution and place it in the reaction tank 16 of the alkali metal reaction tank 11. Use the hot plate 10 to heat the alkali metal reaction tank 11 to 100°C to dry out the moisture, then heat it to 150°C to remove water vapor. Then, evacuate the alkali metal reaction tank 11 and heat it to 180°C to remove water vapor. After completion, place the pre-gas chamber wafer unit on the cold plate 14 and cool it to room temperature. Then, align the pre-gas chamber wafer unit with the channel plate 13 and the positioning column 12, stack them in sequence, and place them on the alkali metal reaction tank 11, thus achieving positive alignment between the pre-gas chamber wafer unit and the alkali metal reaction tank 11.

[0084] The alkali metal reaction pool 11 is heated by a hot plate, causing the reaction mixture in the alkali metal reaction pool 11 to undergo a chemical reaction to generate alkali metal vapor, which moves upward. The alkali metal vapor passes through the channel plate 13 and is then deposited in the gas chamber slots 4 at the cold end. After waiting for a certain period of time, the pre-gas chamber wafer unit is removed and placed on a cold plate 14 to cool to room temperature. At this time, the alkali metal 7 is deposited in each gas chamber slot 4.

[0085] Furthermore, a low-temperature pre-bonding is performed using an anodic bonding machine. During the low-temperature pre-bonding, the gas chamber packaging wafer 8 is located on the pre-gas chamber wafer unit;

[0086] During low-temperature pre-bonding, the temperature of the bonding head of the anodic bonding equipment is 150°C to 350°C, and the anodic bonding chamber is in a high vacuum state or filled with buffer gas pressure;

[0087] During pre-bonding, the bonding pressure is 0.2MPa~0.4MPa, and the working voltage of the anodic bonding machine is 0V~300V, so that the bonding interface between the gas chamber packaging wafer 8 and the pre-gas chamber wafer unit is pre-bonded, and after the pre-bonding occurs at the bonding interface, the pre-bonding state is stopped.

[0088] In practice, the prepared pre-gas chamber wafer unit typically undergoes organic cleaning, SPM cleaning, and DHF cleaning, followed by vacuum evacuation and heating to remove moisture. The pre-gas chamber wafer is then placed on a cold plate 14 to cool to room temperature. Furthermore, the gas chamber packaging wafer 8, channel plate 13, and positioning pins 12 are each subjected to vacuum evacuation and heating to remove moisture. Afterwards, they are placed on a cold plate 14 to cool to room temperature.

[0089] Specifically, before the pre-gas chamber wafer unit is aligned with the alkali metal evaporation device, the pre-gas chamber wafer unit is vacuumed and heated to remove moisture. Furthermore, before the gas chamber packaging wafer 8 is pre-bonded to the pre-gas chamber wafer unit at low temperature, the gas chamber packaging wafer 8 is vacuumed and heated to remove moisture. This improves stability and reliability during the alkali metal evaporation process. Gas chamber packaging wafer 8 can be a glass wafer.

[0090] The anodic bonding chamber is in a high vacuum state or filled with a buffer gas pressure state, generally referring to the pressure of the anodic bonding chamber being 12000Pa~1.0*10 -3 The operating voltage of the anodic bonding machine is specifically related to its operation. Setting the operating voltage to 0V to 300V can meet the required pre-bonding requirements. When the bonding interface between the gas chamber packaging unit 8 and the pre-gas chamber wafer unit is pre-bonded, the gas chamber packaging unit 8 can be used to seal the gas chamber slot 4, thereby sealing the deposited alkali metal 7 in the gas chamber slot 4.

[0091] Figure 8 In the figure, an embodiment of bonding by an anodic bonding machine is shown. The anodic bonding machine generally includes a lower bonding head 18, an upper bonding head 19 and a bonding fixture 20. The upper bonding head 18 and the lower bonding head 19 are used to provide bonding pressure, and the bonding fixture 20 is used to achieve support during bonding. The specific forms of the lower bonding head 18, the upper bonding head 19 and the bonding fixture 20 can be selected according to actual needs, and the specific method and process for achieving anodic bonding can be consistent with the existing ones.

[0092] Furthermore, high temperature anodic bonding is performed using an anodic bonding machine, wherein:

[0093] During high-temperature anodic bonding, the operating voltage of the anodic bonding machine is 800V to 1000V, and the temperature of the bonding head is 320°C to 350°C.

[0094] Specifically, during high-temperature anodic bonding, the starting temperature is higher than the pre-bonding temperature described above. As can be seen from the above description, setting the operating voltage of the anodic bonding machine to 800V to 1000V is sufficient for high-temperature anodic bonding. The criterion for determining anodic bonding completion is when the operating current drops below 1mA. The specific method for determining the anodic bonding status can be selected based on actual needs, with the most effective method for determining the high-temperature anodic bonding status being the most effective.

[0095] During specific implementation, the air chamber slot 4 of the pre-air chamber wafer unit is first sealed by pre-bonding in a low pressure or vacuum environment and a low bonding temperature, and then the pre-air chamber wafer unit is heated to a high temperature in the background vacuum environment of the bonding chamber for a second anodic bonding, thereby solving the problem of alkali metal easily escaping due to heat, ensuring the performance of the formed alkali metal air chamber, and ensuring the requirements of bonding air tightness and bonding strength.

[0096] In one embodiment of the present invention, after high-temperature anodic bonding, when the temperature of the bonding head of the anodic bonding machine drops to 150° C. to 200° C., the pressure of the bonding head is removed, and the vacuum of the anodic bonding chamber is broken to obtain an air chamber wafer packaging unit;

[0097] The gas chamber wafer packaging unit is cut to obtain a single-cavity alkali metal gas chamber formed by a gas chamber hole groove 4 .

[0098] As can be seen from the above description, multiple air chamber holes 4 are prepared in the air chamber main wafer 1 at the same time, and the air chamber packaging wafer 8 is bonded and fixed to the air chamber main wafer 1 to achieve the sealing of the multiple air chamber holes 4, such as Figure 6 shown. Figure 6 In the embodiment, an alkali metal gas chamber 9 can be formed by using a closed gas chamber hole 4. Figure 6 The packaging structure can be cut to obtain a single-cavity alkali metal gas chamber formed by a gas chamber hole groove 4, that is, after cutting, a plurality of alkali metal gas chambers 9 can be obtained.

[0099] In summary, a wafer-level alkali metal gas cell device is prepared using the above-mentioned preparation method.

[0100] Specifically, the process of preparing the wafer-level alkali metal gas chamber device using the above-mentioned preparation method can refer to the above description, which will not be repeated here.

[0101] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for preparing a wafer-level alkali metal gas chamber, characterized in that: The preparation method comprises: preparing a pre-gas chamber wafer unit, wherein the pre-gas chamber wafer unit comprises a plurality of gas chamber holes (4) for receiving alkali metals; The pre-gas chamber wafer unit prepared above is aligned with an alkali metal evaporation device for generating alkali metal vapor, wherein the alkali metal evaporation device includes an alkali metal reaction pool (11) having a plurality of reaction pool slots (16), and the gas chamber slots (4) in the pre-gas chamber wafer unit are aligned one by one with the reaction pool slots (16) of the alkali metal reaction pool (11), so that one gas chamber slot (4) and the corresponding reaction pool slot (16) form an alkali metal supply channel; The alkali metal material pre-placed in the reaction pool (16) is heated and evaporated, and after the heating and evaporation, the alkali metal is deposited in the corresponding gas chamber hole groove (4) using the above-mentioned alkali metal giving channel, and after the required alkali metal is deposited in the gas chamber hole groove (4), the pre-gas chamber wafer unit is cooled to room temperature; Providing a gas chamber packaging wafer (8), and performing low-temperature pre-bonding on the gas chamber packaging wafer (8) and the pre-gas chamber wafer unit cooled to room temperature, so that after the low-temperature pre-bonding, the gas chamber hole groove (4) in the pre-gas chamber wafer unit is sealed by the gas chamber packaging wafer (8); The low-temperature bonded gas chamber packaging wafer (8) and the pre-gas chamber wafer unit are subjected to high-temperature anodic bonding, wherein during the high-temperature anodic bonding, the bonding gas pressure is in a molecular pump background vacuum state.

2. The method for preparing a wafer-level alkali metal gas cell according to claim 1, wherein: The pre-gas chamber wafer unit comprises a gas chamber main wafer (1) and a gas chamber auxiliary wafer (6) bonded and fixed to one surface of the gas chamber main wafer (1), wherein: The air chamber hole groove (4) passes through the air chamber main wafer (1), and the air chamber auxiliary wafer (6) is used to close a notch of the air chamber hole groove (4); When the air chamber packaging wafer (8) is pre-bonded to the pre-air chamber wafer unit, the air chamber packaging wafer (8) is bonded and fixed to the other surface of the air chamber main wafer (1), so that all the air chamber holes (4) in the air chamber main wafer (1) are sealed by using the air chamber packaging wafer (8) and the air chamber auxiliary wafer (6).

3. The method for preparing a wafer-level alkali metal gas cell according to claim 2, wherein: The gas chamber main wafer (1) comprises a silicon wafer, and the gas chamber auxiliary wafer (6) and the gas chamber packaging wafer (8) both comprise glass wafers; The bonding and fixing method of the gas chamber auxiliary wafer (6) and the gas chamber main wafer (1) includes anodic bonding.

4. The method for preparing a wafer-level alkali metal gas chamber according to claim 2, wherein: The gas chamber main wafer (1) also includes an alkali metal positioning channel (5), wherein the alkali metal positioning channel (5) passes through the gas chamber main wafer (1); The alkali metal evaporation device comprises a plurality of positioning posts (12) capable of extending into an alkali metal positioning channel (5), a hot plate (10) for providing a heat source, and a cold plate (14) for providing a cold source, wherein: The positioning post (12) is provided on the alkali metal reaction pool (11), and the positioning post (12) is aligned and connected with the alkali metal positioning channel (5), so that the pre-gas chamber wafer unit and the alkali metal reaction pool (11) are aligned. A hot stage (10) is used to provide a heat source for evaporating the alkali metal material in the alkali metal reaction pool (11), and a cold plate (14) is used to cool the alkali metal entering the gas chamber hole groove (4), so that the alkali metal is deposited in the gas chamber hole groove (4).

5. The method for preparing a wafer-level alkali metal gas cell according to any one of claims 1 to 4, characterized in that: Performing low-temperature pre-bonding using an anodic bonding machine, wherein during the low-temperature pre-bonding, the air chamber packaging wafer (8) is located on the pre-air chamber wafer unit; During low-temperature pre-bonding, the temperature of the bonding head of the anodic bonding equipment is 150°C to 350°C, and the anodic bonding chamber is in a high vacuum state or filled with buffer gas pressure; During pre-bonding, the bonding pressure is 0.2MPa to 0.4MPa, and the working voltage of the anodic bonding machine is 0V to 300V, so that the bonding interface between the air chamber packaging wafer (8) and the pre-air chamber wafer unit is pre-bonded, and after the pre-bonding occurs at the bonding interface, the pre-bonding state is stopped.

6. The method for preparing a wafer-level alkali metal gas cell according to any one of claims 1 to 4, characterized in that: High temperature anodic bonding is performed using an anodic bonding machine, wherein: During high-temperature anodic bonding, the operating voltage of the anodic bonding machine is 800V to 1000V, and the temperature of the bonding head is 320°C to 350°C.

7. The method for preparing a wafer-level alkali metal gas chamber according to claim 6, wherein: After high-temperature anodic bonding, when the temperature of the bonding head of the anodic bonding machine drops to 150°C to 200°C, the pressure of the bonding head is removed and the vacuum of the anodic bonding chamber is broken to obtain an air chamber wafer packaging unit; The gas chamber wafer packaging unit is cut to obtain a single-cavity alkali metal gas chamber formed by a gas chamber hole groove (4).

8. The method for preparing a wafer-level alkali metal gas cell according to any one of claims 1 to 4, characterized in that: Before the pre-gas chamber wafer unit is aligned with the alkali metal evaporation device, the pre-gas chamber wafer unit is first vacuumed and heated to remove moisture, and Before the air chamber packaging wafer (8) is pre-bonded to the pre-air chamber wafer unit at low temperature, the air chamber packaging wafer (8) is subjected to a vacuum heating and dehumidification treatment.

9. The method for preparing a wafer-level alkali metal gas cell according to any one of claims 1 to 4, characterized in that: The alkali metal substance (17) preset in the alkali metal reaction tank (11) includes alkali metal droplets and / or alkali metal alloys.

10. A wafer-level alkali metal gas cell device, characterized in that: The wafer-level alkali metal gas chamber device is prepared by using the preparation method of any one of claims 1 to 9 above.

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