Reaction chamber apparatus for powder fluidized atomic layer deposition and methods of use thereof

Abstract

The application belongs to the technical field of atomic layer deposition coating, and particularly relates to a reaction cavity device for powder fluidization atomic layer deposition and a use method thereof. The reaction cavity device comprises a reaction cavity body, a bottom gas inlet, a top gas outlet, a reaction cavity bypass and a purge gas branch. The reaction cavity bypass is a gas conveying pipeline connected in parallel with a gas conveying main pipeline of the reaction cavity. The bypass starts from a bottom gas inlet end of the reaction cavity, ends at a diaphragm valve of the top gas outlet end of the reaction cavity, and is controlled to be opened by a control valve. The bottom filter is a metal powder sintered filter with non-uniform pores. The top filter is coupled with a temperature measuring plug-in and a gas purge branch. The application disperses the powder in the reaction cavity from bottom to top by using fluidization gas, effectively improves the residual gas extraction efficiency of the powder fluidization atomic layer deposition, suppresses the height of the powder dilute phase layer, monitors the internal temperature of the reaction cavity, blows off the attached powder on the top filter, and effectively fluidizes the powder in the reaction cavity.

Description

Technical Field

[0001] This invention belongs to the field of atomic layer deposition coating technology, specifically relating to a reaction chamber device for powder fluidized atomic layer deposition and its usage method. Background Technology

[0002] To impart specific chemical and physical properties to powder particles, their surfaces are typically coated to achieve surface modification. Common methods for powder particle surface coating include solid-phase, liquid-phase, and gas-phase methods. Atomic layer deposition (ALD) is a chemical vapor deposition method that involves alternating introduction of precursor gases to induce a self-limiting and self-saturating surface reaction on the object to be coated. This method allows for precise control of atomic-layer thickness by controlling the number of precursor cycles. Therefore, ALD has significant advantages over solid-phase, liquid-phase, and gas-phase deposition methods. Commonly used powder ALD methods include fixed-bed ALD, rotating-bed ALD, and fluidized bed ALD. Fluidized bed ALD, in particular, disperses the powder using a fluidizing gas to achieve the ALD reaction, offering advantages such as the ability to disperse ultrafine powders and scalable experimental setups.

[0003] For a vertically positioned reaction chamber where fluidizing gas enters from bottom to top to fluidize the powder, during the vacuuming stage before coating, if the gas enters from the bottom inlet of the reaction chamber, passes through the bottom filter and accumulated powder, and is then exhausted from the outlet, two problems arise. First, the powder in the reaction chamber will fill the entire upper space due to the vacuuming process, resulting in powder loss. Second, the vacuuming efficiency will decrease because the exhaust pipe passes through the filter and accumulated powder. Furthermore, the contact area between the powder and the inner wall of the reaction chamber is a relatively difficult area to fluidize, especially for fine powders, which tend to accumulate on the inner wall, affecting the powder dispersion efficiency.

[0004] Chinese invention patent CN103451623A discloses an atomic layer deposition method and apparatus for coating ultrafine powders. Although it uses fluidizing gas to disperse the powder, the fluidization method at the gas inlet is insufficient, and the powder in the inner wall area of ​​the reaction chamber may not be sufficiently fluidized and dispersed. Furthermore, Chinese patents CN202110454248.5 and CN202120874022.6 disclose methods to prevent powder adhesion to the inner wall by tapping the reaction chamber, while Chinese patent CN202120874313.5 discloses a powder atomic layer deposition apparatus with a vibration device. This method, relying on external force, may lead to instability in the gas flow field within the powder and loosen the mechanical parts of the reaction chamber system, affecting the performance of the reaction chamber. Summary of the Invention

[0005] The purpose of this invention is to provide a reaction chamber device for powder fluidized atomic layer deposition and its usage method, so as to effectively extract the vacuum of the reaction chamber device, suppress the height of the dilute phase layer, and effectively fluidize the powder in the reaction chamber.

[0006] This invention provides a reaction chamber apparatus for powder fluidized atomic layer deposition, wherein a fluidizing gas is introduced to disperse the powder from bottom to top. The reaction chamber apparatus includes a reaction chamber body, an inlet, an outlet, a reaction chamber bypass, and a purge gas branch; wherein:

[0007] The reaction chamber body is made of stainless steel or Kovar alloy tubing sealed with quartz glass. The reaction chamber body is divided into a fluidization section, a transition section, and an expansion section. Specifically, the fluidization section and the expansion section are cylindrical, with the diameter of the expansion section being larger than that of the fluidization section. The two are connected by a transition section, which is frustum-shaped. The angle between the generatrix of the frustum and the vertical direction (also called the transition angle) is 7–15° (see [reference]). Figure 3 ).

[0008] Preferably, the ratio of the length of the fluidization section to the sum of the lengths of the intermediate transition section and the expansion section is 1 to 1.5.

[0009] The air inlet is located at the bottom of the reaction chamber, and a filter is installed at the air inlet. This filter is made of sintered stainless steel or titanium powder. The filter's specific structure consists of one or more of the following combinations:

[0010] (1) Single-pore cylindrical filter, with pore size of 10-20 micrometers and thickness of 1-2 mm;

[0011] (2) Non-uniform pore cylindrical filter, with the middle part of the filter having a pore size of 5 to 15 micrometers and the outer ring having a pore size of 15 to 20 micrometers. The middle filter is embedded in the center of the outer ring filter to form a whole, and the overall thickness of the filter is 1 to 2 mm.

[0012] (3) Non-uniform pore filter, which has a double-layer structure; the upper layer consists of a large pore filter (pore size 15-20 micrometers) and a small pore cylindrical ring filter (pore size 5-15 micrometers), with the large pore filter embedded in the center of the small pore cylindrical ring filter to form the upper filter structure; the lower filter is a large pore filter (pore size 15-20 micrometers), and the upper filter is stacked on top of the lower filter to form the filter as a whole, with the thickness of the filter as a whole being 1-3 mm;

[0013] (4) Non-uniform pore filter, wherein the filter has a three-layer structure; upper layer: a small-pore cylindrical ring filter (pore size 5-15 micrometers) with a large-pore cylindrical filter (pore size 15-20 micrometers) embedded in the center; middle layer: a non-porous metal support ring (wall thickness 1-5 mm, height 1-3 mm); lower layer: a large-pore cylindrical filter (pore size 15-20 micrometers), wherein the upper, middle and lower filter layers are stacked to form a filter whole, and the thickness of the filter whole is 1-5 mm.

[0014] Preferably, the air inlet filter is made of 316L stainless steel powder sintered filter or titanium metal powder sintered filter.

[0015] Preferably, the air inlet filter has a structure with large pores in the middle part and small pores in the outer ring. The middle part of the filter has pores of 15 to 20 micrometers, the outer ring filter has pores of 10 to 15 micrometers, and the entire filter is 2 mm thick.

[0016] Preferably, the cylindrical ring filter is embedded in a small cylindrical filter structure, and the outer diameter of the small cylindrical filter is 1 / 4 to 1 / 2 of the outer diameter of the cylindrical ring.

[0017] The gas outlet is located at the top of the reaction chamber and is connected to an external vacuum pump. A diaphragm valve is installed on the connecting pipeline. The vacuum pump is used for evacuating the device and treating the exhaust gas.

[0018] A filter is installed below the air outlet (i.e., at the expansion section). The filter has no less than 3 filter elements. The filter elements are hollow cylindrical filter elements made of sintered stainless steel or titanium powder. The filter element pore size is 10 micrometers to 20 micrometers. The filter element wall thickness is 2 to 3 mm.

[0019] Preferably, the pore size of the cylindrical filter element is 10 micrometers.

[0020] The reaction chamber bypass is a gas delivery pipeline connected in parallel with the main gas delivery pipeline of the reaction chamber. This bypass starts at the bottom inlet of the reaction chamber and connects to the diaphragm valve at the outlet of the reaction chamber. A control valve is installed on the bypass to control its on / off state. The reaction chamber bypass is mainly used for vacuuming and purging operations of the reaction chamber.

[0021] The method of using the reaction chamber bypass is as follows:

[0022] The first step, when evacuating the reaction chamber, is to open the control valve on the bypass of the reaction chamber. The gas is then drawn out of the reaction chamber by the vacuum pump system through the control valve.

[0023] The second step is to close the control valve on the bypass of the reaction chamber, open the diaphragm valve at the gas outlet of the reaction chamber, and perform vacuuming and gas purging on the main pipeline of the reaction chamber.

[0024] By using a reaction chamber bypass, the system's vacuuming efficiency can be improved, and under the same conditions, the gas extraction efficiency can be increased by 50% to 100%.

[0025] By using a reaction chamber bypass, the height of the dilute phase layer of powder in the reaction chamber can be effectively suppressed during vacuuming.

[0026] The purge gas branch is located at the gas outlet at the top of the reaction chamber and is connected to the purge gas connecting pipeline. The connecting pipeline is equipped with a mass flow controller and a solenoid valve to control the purge gas flow rate.

[0027] A temperature penetration component is also provided at the air outlet at the top of the reaction chamber, and the component is isolated from the internal environment of the reaction chamber by a filter element.

[0028] Preferably, the temperature penetration device is a PT100 resistance temperature detector (RTD) sensor or a K-type thermocouple sensor.

[0029] The top filter is coupled to the temperature sensor insertion plug and the gas purging branch;

[0030] The main functions of the purge gas branch are as follows: During the powder coating process, the fluidizing gas disperses the powder from bottom to top, causing the powder to adhere to the filter at the top outlet of the reaction chamber. The purge gas branch intermittently purges the powder adhering to the filter, effectively removing the powder adhering to the filter. After the coating reaction is completed, the vacuum in the reaction chamber can also be broken by controlling the control valve on the purge gas branch.

[0031] The filter structure with large central pores and small outer ring pores can effectively fluidize and disperse powder in the sidewall region of the reaction chamber.

[0032] Preferably, the pore size of the middle filter is 15-20 micrometers, and the pore size of the outer ring filter is 10-15 micrometers.

[0033] The reaction chamber device of the present invention further includes a precursor delivery branch and a fluidizing gas delivery branch; the precursor delivery branch and the fluidizing gas delivery branch are connected to the main intake pipe of the reaction chamber, and the fluidizing gas delivery branch is at the front end of the precursor delivery branch, so that when the precursor gas is delivered to the main intake pipe, the fluidizing gas can carry the precursor gas into the main intake pipe.

[0034] The main intake pipe is connected to a four-way flange, and the four-way flange is connected to the bottom flange of the reaction chamber body through a stainless steel connecting pipe, so that the gas in the main intake pipe enters the reaction chamber body in sequence through the four-way flange, the connecting pipe and the bottom flange of the reaction chamber.

[0035] The method of using the reaction chamber device is as follows:

[0036] The first step is to use the vacuum system to evacuate and purge the bottom inlet pipe, the precursor delivery branch, and the fluidizing gas delivery branch of the reaction chamber and their corresponding control valves through the reaction chamber bypass. Then, close the control valve on the reaction chamber bypass, open the control valve of the reaction chamber outlet, and evacuate the upper pipe of the powder accumulation inside the reaction chamber and the purging gas pipe.

[0037] The second step is to heat the reaction chamber containing the powder to a temperature of 150-300℃ and keep it at that temperature for more than 1 hour. Then, turn on the fluidizing gas delivery branch and adjust the fluidizing gas speed so that the gas velocity at the bottom inlet of the reaction chamber is 1cm / s-10cm / s. The powder in the reaction chamber is fluidized and dispersed for more than 5 minutes.

[0038] Step 3: Maintain continuous vacuum pumping and continuous flow of fluidizing gas, controlling the pressure difference between the outlet and inlet to be approximately 133 Pa to 1330 Pa; (i) Using the precursor delivery system, introduce the precursor 1 to be reacted 1 pulse 1 to 10 times, with a single flow rate of 30 sccm-100 sccm and a pulse duration of 30 ms to 100 ms; (ii) Stop the delivery of the precursor 1 to be reacted and flush the reaction chamber with fluidizing gas for 60 s to 180 s; (iii) Introduce the precursor 2 to be reacted 1 pulse 1 to 10 times, with a single flow rate of 30 sccm-100 sccm and a pulse duration of 30 ms to 100 ms; (iv) Stop the delivery of the precursor 2 to be reacted and flush the reaction chamber with fluidizing gas for 60 s to 180 s; Repeat steps (i) to (iv) according to the required coating thickness.

[0039] Fourth step: During the coating process in the third step, the gas purging branch solenoid valve is intermittently opened to purge the filter at the top of the reaction chamber to remove the adhering powder.

[0040] Fifth step: After the coating is completed, wait for the temperature of the reaction chamber to drop to room temperature, close the gas outlet valve of the reaction chamber, and use the gas purging branch to break the vacuum in the reaction chamber.

[0041] Compared with existing products, the present invention has the following advantages:

[0042] (1) By utilizing the reaction chamber bypass and method of the present invention, the residual gas in the gas pipeline can be quickly and cleaned during the vacuum preparation stage of powder fluidized atomic layer deposition coating, thereby improving the efficiency of residual gas extraction in the pipeline.

[0043] (2) The reaction chamber device and method of the present invention can effectively suppress the height of the powder dilute phase layer during the vacuuming stage, which facilitates the blowing of powder adhering to the filter and the breaking of the vacuum.

[0044] (3) The powder in the area near the inner wall of the reaction chamber can be effectively dispersed by using the reaction chamber device and method. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the vacuuming process for the reaction chamber device.

[0046] Figure 2 This is a schematic diagram of the coating process for the reaction chamber device.

[0047] Figure 3 This is a schematic diagram of the powder fluidized atomic layer deposition reaction chamber device and gas path.

[0048] Figure 4 This is a schematic diagram of a uniform pore filter I.

[0049] Figure 5 This is a schematic diagram of a non-uniform pore filter II.

[0050] Figure 6 This is a schematic diagram of a non-uniform pore filter III.

[0051] Figure 7 This is a schematic diagram of a non-uniform pore filter IV.

[0052] Figure 8 A comparison of the dilute phase layer height with and without using the reaction chamber bypass exhaust.

[0053] Figure 9 The image shows the bed structure (left) and the schematic diagram of powder fluidization (right) when using a uniform pore filter I to fluidize powder (apparent gas velocity of fluidizing gas is 1.37 cm / s).

[0054] Figure 10 The image shows the bed (left) and the powder fluidization diagram (right) when using a non-uniform pore filter II to fluidize powder (apparent gas velocity of 1.37 cm / s).

[0055] Figure 11 The image shows the bed structure (left) and the schematic diagram (right) of powder fluidization using a non-uniform pore filter II (apparent gas velocity of fluidizing gas is 1.50 cm / s).

[0056] Labels in the diagram: 1—Sintered metal powder filter, 2—Reaction chamber, 3—Transition angle, 4—Sintered metal powder cylindrical filter element, 5—Top flange, 6—Temperature measuring insert, 7—Mass flow controller, 8—Solenoid valve, 9—Diaphragm valve, 10—Third vacuum gauge, 11—Second vacuum gauge, 12—Bypass control valve, 13—Four-way flange, 14—First vacuum gauge, 15—Bottom flange, 16—Inlet, 17—Outlet, 18—Reaction chamber bypass, 19—Purge gas branch, 20—Main inlet pipe, 21—Stainless steel connecting pipe, 22—Reaction chamber heater, 23—Large-pore sintered metal powder filter, 24—Small-pore sintered metal powder filter ring, 25—Non-uniform pore filter II assembled from 23 and 24, 26—Cross-sectional view of filter II. 27, 29—Sintered filter sheet with large porosity metal powder; 28—Sintered filter ring with small porosity metal powder; 30—Non-uniform porosity filter sheet III assembled from 27, 28, and 29; 31—Cross-sectional view of filter sheet III. 32, 35—Sintered filter sheet with large porosity metal powder; 33—Sintered filter ring with small porosity metal powder; 34—Non-porous metal support ring; 36—Non-uniform porosity filter sheet IV assembled from 32, 33, 34, and 35; 37—Cross-sectional view of filter sheet IV. Detailed Implementation

[0057] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0058] Example 1, Vacuuming process of powder fluidized atomic layer reaction chamber device, such as Figure 1 As shown, the specific process is as follows:

[0059] S11: Turn on the vacuum pump, close the diaphragm valve 9 at the gas outlet 17 of the reaction chamber, and open the control valve 12 of the bypass 18 of the reaction chamber.

[0060] S12: Continuously turn on the vacuum pump to extract the gas in the fluidized gas delivery branch pipe and the precursor delivery branch pipe, and extract the gas inside the reaction chamber 2 from top to bottom.

[0061] S13: Close the bypass control valve 12, open the diaphragm valve 9 at the gas outlet 17 of the reaction chamber, and extract the remaining gas in the reaction chamber 2 from bottom to top. At the same time, open the control valve 8 of the purge gas branch 19 to extract the gas.

[0062] Example 2, the coating process of the reaction chamber device is as follows Figure 2 As shown, specifically:

[0063] Turn on the heating device 22 of the reaction chamber, and after the thermometer 6 in the reaction chamber 2 reaches the process temperature (100℃~300℃), keep it at that temperature for more than 1 hour, and then carry out the following steps.

[0064] S21: Keep the vacuum pump running, open the diaphragm valve 9 at the gas outlet 17 of the reaction chamber, and close the control valve 12 of the bypass 18 of the reaction chamber.

[0065] S22: Different types of precursors are alternately introduced through the precursor delivery branch, and fluidizing gas is continuously introduced to disperse the powder in the reaction chamber 2 in a fluidized state. The pressure drop of the bed in the reaction chamber is monitored by the first vacuum gauge 14 and the second vacuum gauge 11 to complete the coating reaction.

[0066] St22: During the implementation of step S22, the powder adhering to the outlet filter 4 is intermittently purged using the purge gas branch 19.

[0067] S23: Repeat step S22 according to the coating thickness requirements.

[0068] S24: After the coating is completed, the reaction chamber 2 and the powder inside it are cooled to room temperature. The vacuum in the reaction chamber 2 is broken by using the purging gas branch 19.

[0069] To further illustrate the method of using the present invention, a schematic diagram of the reaction chamber device is now provided. Figure 3 This describes the specific steps for vacuuming using the present invention.

[0070] The first step is to turn on the vacuum pump, close the diaphragm valve 8 at the gas outlet 17 of reaction chamber 2, and open the control valve 12 of the reaction chamber bypass 18. This opens the gas delivery path from the vacuum pump to the four-way flange 13 of the reaction chamber. Therefore, the washing gas from the fluidizing gas delivery branch pipeline, the precursor delivery branch pipeline, and the diaphragm valve position of the precursor source bottle can all be drawn by the vacuum pump through this gas delivery path.

[0071] Furthermore, because the diaphragm valve 9 at the gas outlet 17 of reaction chamber 2 is closed, the gas in reaction chamber 2 can only be drawn from top to bottom through the accumulated powder and the filter 1 and flange 15 at the bottom of the reaction chamber. Vacuum is evacuated until the vacuum gauge 10 reaches below 20 Pa.

[0072] The second step involves keeping the vacuum pump running, closing the control valve 12 on the reaction chamber bypass 18, and opening the diaphragm valve 9 at the gas outlet 17 of the reaction chamber 2 to establish a gas delivery pipeline from the vacuum pump to the reaction chamber 2. Because the gas below the powder accumulation in the reaction chamber 2 was pre-evacuated during the first step, the height of the dilute phase layer caused by the vacuum evacuation in the reaction chamber 2 will be effectively suppressed during this step.

[0073] Meanwhile, during this step, unwanted gas in the purge gas branch pipeline will also enter the diaphragm valve 9 through the reaction chamber 2 and be extracted by the vacuum pump.

[0074] The third step is to adjust the appropriate flow rate of the fluidizing gas and use the fluidizing gas delivery branch to perform an appropriate gas washing step on the powder in the reaction chamber 2 through the main pipeline 20, four-way flange 13, connecting pipe 21, bottom flange 15 and filter 1.

[0075] To further illustrate the role of the main components of the present invention in powder fluidized atomic layer deposition, Example 2 will be used as a reference.

[0076] First, after the coating begins, open the diaphragm valve 9 at the gas outlet 17 of the reaction chamber 2, close the control valve 12 of the reaction chamber bypass 18, and continuously introduce nitrogen gas through the fluidizing gas delivery branch. The apparent gas velocity of the fluidizing gas is 1.0 cm / s. The powder in the reaction chamber 2 will be fluidized and dispersed in the fluidization section, and the fluidizing gas will be extracted from the reaction chamber 2 by the vacuum pump through the filter 4 at the gas outlet flange 5.

[0077] The second step involves heating reaction chamber 2. When the temperature of the temperature sensing insert 6 reaches 150°C, trimethylaluminum and deionized water are alternately introduced multiple times via the precursor delivery branch. After each precursor pulse, the chamber is flushed with fluidizing gas for 10 seconds to allow the trimethylaluminum and water to react on the powder surface within reaction chamber 2. The pressure drop of the fluidized bed within the reaction chamber can be monitored using vacuum gauges 14 and 11. Vacuum gauge 10 can be used as the input value for the closed-loop control of the vacuum pump, controlling the pump's evacuation.

[0078] Third, repeat step 2 according to the required coating thickness. During the powder fluidization and coating process, although there is a transition angle of ~9° in the transition section of the reaction chamber, which reduces the flow rate of powder reaching the outlet, fine powder will adhere to the filter 4. The solenoid valve 8 on the gas purging branch 19 can be opened intermittently to purge the powder from the filter.

[0079] Fourth step: After the coating process is completed, dry and pure nitrogen gas is introduced into the reaction chamber 2 through the solenoid valve 8 of the gas purging branch 19 to break the vacuum.

[0080] In this invention, Figure 3 In the reaction chamber device shown, filter 1 is a sintered stainless steel filter or a sintered titanium filter, and its structure can be one or a combination of the following four structures.

[0081] (1) Single-pore cylindrical filter I, with pore size of 10-20 micrometers and thickness of 1-2 mm, filter I as follows Figure 4 As shown.

[0082] (2) Non-uniform pore cylindrical filter II, the middle part 23 filter has a pore size of 5-15 micrometers, the outer ring part 24 filter has a pore size of 15-20 micrometers, and the thickness is 1-2 mm. The structure of filter II is as follows. Figure 5 As shown.

[0083] (3) Non-uniform pore filter III, which has a double-layer structure. The upper layer consists of a large-pore filter 27 (pore size 15-20 micrometers) and a small-pore cylindrical ring filter 28 (pore size 5-15 micrometers), and the lower layer consists of a large-pore filter 29 (pore size 15-20 micrometers). The overall thickness of filter III is 1-3 mm. The structure of filter III is as follows: Figure 6 As shown.

[0084] (4) Non-uniform pore filter IV, which has a three-layer structure. Upper layer: Composed of a large-pore filter 32 (pore size 15-20 micrometers) and a small-pore cylindrical ring filter 33 (pore size 5-15 micrometers); Middle layer: Non-porous metal support ring 34 (wall thickness 1-5 mm, height 1-3 mm); Lower layer: Large-pore cylindrical filter 35 (pore size 15-20 micrometers). The overall thickness of filter IV is 1-5 mm. A schematic diagram of filter IV is shown below. Figure 7 As shown.

[0085] Example 3: Comparison of dilute phase layer height with and without using the reaction chamber bypass exhaust, as shown in the figure. Figure 8 As shown.

[0086] To illustrate the practical effects of this invention, a reaction chamber made of quartz glass was used in this embodiment. A uniform pore size filter I with 10 micrometers of pore size and a thickness of 2 mm was used. The selected powder was 80-100 mesh quartz sand powder, weighing 30 g. The powder bed conditions were compared when vacuuming was performed with and without a reaction chamber bypass.

[0087] Process I: Close the control valve 12 on the reaction chamber bypass 18 of the present invention, open the diaphragm valve 9 at the gas outlet 17 of the reaction chamber 2, and directly evacuate the system.

[0088] Process II: Vacuuming is performed on the reaction chamber system of the present invention using the steps described in Example 1.

[0089] The results of process I and process II are as follows Figure 8 As shown. Figure 8 The left image shows the powder bed when the powder is stationary; the middle image shows the powder bed during process I; and the right image shows the powder bed during process II. Using the reaction chamber bypass 18 of this invention, through the steps of Example 1, the height of the dilute phase layer of the powder in the reaction chamber 2 can be effectively suppressed during the vacuuming stage.

[0090] Example 4 illustrates the effect of different filter structures on powder fluidization within the reaction chamber by comparing filter structure I and filter structure II. Filter structure I is a cylindrical sintered stainless steel powder filter with a pore size of 10 micrometers and a thickness of 2 mm. Filter structure II, with a non-uniform pore size, has a thickness of 2 mm, with a central filter element 23 having a pore size of 20 micrometers and an outer ring filter element 24 having a pore size of 10 micrometers. The diameter of the central cylindrical filter element 23 is half the diameter of the overall filter structure II. In this example, 80-100 mesh quartz sand was used, with a powder weight of 35 g, and dry nitrogen was used as the fluidizing gas.

[0091] (1) Powder fluidization when using filter element I

[0092] When the apparent gas velocity of the fluidizing gas introduced into the reaction chamber from bottom to top is 1.37 cm / s, fluidization of the powder occurs uniformly in the region of the powder bed deviating from the reaction chamber wall, such as... Figure 9 As shown in the image on the left, specifically, in the central region of the bed, the fluidizing gas carries the powder from bottom to top to the upper part of the bed, where it then disperses to the surrounding area. The fluidization is not intense, as... Figure 9 As shown in the diagram on the right.

[0093] (2) Powder fluidization when using filter construction II

[0094] When the apparent gas velocity of the fluidizing gas introduced into the reaction chamber from bottom to top is 1.37 cm / s, powder fluidization tends to occur in the contact area between the powder and the reaction chamber, such as... Figure 10 As shown in the image on the left, specifically in the area where the reaction chamber contacts the powder, the fluidizing gas carries the powder from bottom to top to the upper part of the bed, where it then disperses to the surrounding area. The fluidization is not intense, as... Figure 10 As shown in the diagram on the right.

[0095] When the apparent flow rate of the fluidizing gas is increased to 1.50 cm / s, compared to the case of a lower fluidizing gas flow rate, the powder in the center of the bed undergoes intense fluidization, while the edge region of the reaction chamber experiences more moderate fluidization, such as... Figure 11 The images on the left and right are shown.

Claims

1. A reaction chamber apparatus for powder fluidized atomic layer deposition, characterized in that, Includes the reaction chamber body, air inlet, air outlet, reaction chamber bypass, and purge gas branch; wherein: The reaction chamber body is made of stainless steel or Kovar alloy tubes sealed with quartz glass, and is divided into a fluidization section, a transition section, and an expansion section. The fluidization section and the expansion section are cylindrical, with the diameter of the expansion section being larger than that of the fluidization section. The two are connected by a transition section, which is a frustum-shaped cone. The angle between the generatrix of the frustum and the vertical direction is 7~15°. The air inlet is located at the bottom of the reaction chamber, and a filter is provided at the air inlet. The filter is made of sintered stainless steel metal powder or titanium metal powder. The gas outlet is located at the top of the reaction chamber body, and the gas outlet end is connected to an external vacuum pump. A diaphragm valve is installed on the connecting pipeline. The vacuum pump is used for vacuuming the device and treating the exhaust gas. A filter is installed below the air outlet, at the enlarged section of the reaction chamber body. The filter has no less than 3 hollow cylindrical filter elements. The filter elements are made of sintered stainless steel or titanium powder, and the filter element pores are 10 micrometers to 20 micrometers. The filter element wall thickness is 2 to 3 mm. The reaction chamber bypass is a gas delivery pipeline connected in parallel with the main gas delivery pipeline of the reaction chamber. The bypass starts at the bottom inlet of the reaction chamber and connects to the diaphragm valve at the outlet of the reaction chamber. A control valve is installed on the bypass to control its on / off state. The reaction chamber bypass is used for vacuuming and gas washing operations of the reaction chamber. The purge gas branch is located at the gas outlet at the top of the reaction chamber and is connected to the purge gas pipeline. The connecting pipeline is equipped with a mass flow controller and a solenoid valve to control the purge gas flow rate. A temperature sensing insert is also provided at the air outlet at the top of the reaction chamber, and the temperature sensing insert is isolated from the internal environment of the reaction chamber by a filter element; The top filter is coupled to the temperature sensor insertion plug and the gas purging branch; The purge gas branch is used to intermittently purge the powder adhering to the filter during the powder coating process; after the coating reaction is completed, the vacuum in the reaction chamber is broken by controlling the control valve on the purge gas branch. It also includes a precursor delivery branch and a fluidizing gas delivery branch; the precursor delivery branch and the fluidizing gas delivery branch are connected to the main intake pipe of the reaction chamber, and the fluidizing gas delivery branch is at the front end of the precursor delivery branch, so that when the precursor gas is delivered to the main intake pipe, the fluidizing gas can carry the precursor gas into the main intake pipe. The main intake pipe is connected to a four-way flange, and the four-way flange is connected to the bottom flange of the reaction chamber body through a stainless steel connecting pipe, so that the gas in the main intake pipe enters the reaction chamber body in sequence through the four-way flange, the connecting pipe and the bottom flange of the reaction chamber. The filter element of the air inlet is constructed from one or a combination of the following: (1) Non-uniform pore filter, which has a double-layer structure; the upper layer is composed of a large pore filter and a small pore cylindrical ring filter, with the large pore filter embedded in the center of the small pore cylindrical ring filter to form the upper filter structure; the lower filter is a large pore filter, and the upper filter is stacked on the lower filter to form the filter as a whole, with the thickness of the filter as a whole being 1~3 mm; wherein, the pore size of the large pore filter is 15~20 micrometers, and the pore size of the small pore cylindrical ring filter is 5~15 micrometers; (2) Non-uniform pore filter, wherein the filter has a three-layer structure; upper layer: a small-pore cylindrical ring filter with a large-pore cylindrical filter embedded in the center; middle layer: a non-porous metal support ring; lower layer: a large-pore cylindrical filter, wherein the upper, middle and lower filter layers are stacked to form a filter as a whole, and the thickness of the filter as a whole is 1~5 mm; wherein the pore size of the small-pore cylindrical ring filter is 5~15 micrometers, and the pore size of the large-pore cylindrical filter is 15~20 micrometers; the wall thickness of the non-porous metal support ring is 1~5 mm, and the height is 1~3 mm.

2. The reaction chamber apparatus for powder fluidized atomic layer deposition according to claim 1, characterized in that, The ratio of the length of the fluidization section of the reaction chamber to the sum of the lengths of the transition section and the expansion section is 1 to 1.

5.

3. The reaction chamber apparatus for powder fluidized atomic layer deposition according to claim 1, characterized in that, The cylindrical ring filter is embedded with a small cylindrical filter, the outer diameter of which is 1 / 4 to 1 / 2 of the outer diameter of the cylindrical ring.

4. The reaction chamber apparatus for powder fluidized atomic layer deposition according to claim 3, characterized in that, The temperature sensing insert is a PT100 resistance temperature detector (RTD) sensor or a K-type thermocouple sensor.

5. The method of using the reaction chamber apparatus for powder fluidized atomic layer deposition as described in any one of claims 1-4, characterized in that, The specific steps are as follows: First, turn on the vacuum pump, close the diaphragm valve at the gas outlet of the reaction chamber, and open the control valve of the reaction chamber bypass. Continue to turn on the vacuum pump to extract the gas in the fluidized gas delivery branch pipeline and the precursor delivery branch pipeline, and extract the gas inside the reaction chamber from top to bottom. Close the bypass control valve, open the diaphragm valve at the gas outlet of the reaction chamber, and extract the remaining gas in the reaction chamber from bottom to top. At the same time, open the control valve of the purge gas branch to extract the gas. The second step is to heat the reaction chamber containing the powder to a temperature of 150~300℃ and keep it at that temperature for more than 1 hour. Then, turn on the fluidizing gas delivery branch and adjust the fluidizing gas speed so that the gas velocity at the bottom air inlet of the reaction chamber is 1 cm / s~10 cm / s. The powder in the reaction chamber is fluidized and dispersed for more than 5 minutes. Step 3: Maintain continuous vacuum pumping and continuous flow of fluidizing gas, controlling the pressure difference between the outlet and inlet to be between 133 Pa and 1330 Pa; (i) Using the precursor delivery system, introduce the precursor 1 to be reacted 1 pulse 1 to 10 times, with a single flow rate of 30 sccm-100 sccm and a pulse duration of 30 ms to 100 ms; (ii) Stop the delivery of the precursor 1 to be reacted and flush the reaction chamber with fluidizing gas for 60s to 180s; (iii) Introduce the precursor 2 to be reacted 1 pulse 1 to 10 times, with a single flow rate of 30 sccm-100 sccm and a pulse duration of 30 ms to 100 ms; (iv) Stop the delivery of the precursor 2 to be reacted and flush the reaction chamber with fluidizing gas for 60s to 180s; Repeat steps (i) to (iv) according to the required coating thickness. Fourth step: During the coating process in the third step, the gas purging branch solenoid valve is intermittently opened to purge the filter at the top of the reaction chamber to remove the adhering powder. Fifth step: After the coating is completed, wait for the temperature of the reaction chamber to drop to room temperature, close the gas outlet valve of the reaction chamber, and use the gas purging branch to break the vacuum in the reaction chamber.

Images