A device and method for depositing thin film on inner wall of tubular workpiece

Abstract

The invention relates to the field of plating technology, and in particular to a device and method for depositing a thin film on the inner wall of a tubular workpiece. The deposition device comprises a deposition chamber, the deposition chamber comprises a reaction chamber, a feed pipeline and a discharge pipeline are arranged on two sides of the reaction chamber, a support device is arranged in the reaction chamber, and the support device is used to place the tubular workpiece to be plated; the outer wall of the tubular workpiece is coated with a flexible heating element, and a heating body is distributed inside the flexible heating element to be plated, which is used to heat the tubular workpiece during the thin film deposition process, and the tubular workpiece is wrapped by the flexible heating element so that the heating body and the tubular workpiece are closely fitted and heated without a gap, and the heating body wraps the tube body to be heated more evenly, and the heat conduction effect is high, which is conducive to the uniform deposition of the thin film on the inner wall of the tube; at the same time, it is supported by the outer layer of the flexible heating element, has good thermal insulation, is conducive to improving the thermal utilization efficiency of the heating body, and is isolated from the support device, reduces the thermal influence of the support device, and is conducive to improving the uniform deposition of the film.

Description

Technical Field

[0001] The invention relates to the technical field of plating, and in particular to a device and method for depositing a thin film on the inner wall of a tubular workpiece. Background Art

[0002] The coating process is a very important part of modern industrial production. The more common and widely used ones are physical vapor deposition technology and chemical vapor deposition technology. Chemical vapor deposition (CVD) technology forms a film layer on the surface of the object by introducing the corresponding reaction gas into the reaction chamber. For chemical vapor deposition technology, the uniformity of the film thickness is a very important indicator, and the uniformity of the film thickness is often affected by various factors such as product shape and size. For example, coating inside the tube, especially the coating on the inner wall of a small-diameter long tube, has long been a difficult problem in the field of chemical vapor deposition technology. This is mainly because the gas in the chamber cannot flow more from the port to the center of the tube. The gas mainly adheres to the two ports of the tube and cannot be evenly dispersed in the tube. The different gas concentrations lead to extremely poor uniformity of the film thickness on the inner wall of the tube, and even the central part of the small-diameter long tube cannot be coated, which seriously affects the product qualification rate. Moreover, the smaller the diameter of the tube and the longer the size, the more extreme this problem is. Summary of the invention

[0003] The object of the present invention is to provide a device and method for depositing a thin film on the inner wall of a tubular workpiece, so as to solve the problem that the existing plating device has poor uniformity in depositing a thin film on the inner wall of a tubular workpiece.

[0004] In the first aspect, an embodiment of the present invention provides a device for depositing a thin film on the inner wall of a tubular workpiece, comprising: a deposition chamber, the deposition chamber comprising a reaction chamber, a feed pipeline and a discharge pipeline are arranged on two opposite sides of the reaction chamber, a support device is arranged in the reaction chamber, and the support device is used to place the tubular workpiece to be plated; the outer wall of the tubular workpiece is coated with a flexible heating element, and a heating body is distributed inside the flexible heating element to be plated, which is used to heat the tubular workpiece during the thin film deposition process.

[0005] Optionally, the flexible heating element comprises cotton cloth, the heating body is a heat conductor made of graphene material, and the heating body is distributed in the cotton cloth.

[0006] Optionally, the flexible heating element completely covers the tubular workpiece, and tightening openings are respectively provided at both ends of the flexible heating element, and the diameter of the tightening openings accounts for 90% to 95% of the inner diameter of the tubular workpiece.

[0007] Optionally, the tightening opening is provided with an air flow hole.

[0008] Optionally, the flexible heating element includes a first end heating segment, N second heating segments and a third end heating segment arranged in sequence, and the heating temperature of the second heating segment is lower than the heating temperature of the first end heating segment and the third end heating segment; wherein N is an integer greater than 1.

[0009] Optionally, the heating temperature of the second heating section is at least 2° C. lower than the heating temperature of the first end heating section and the third end heating section.

[0010] Optionally, the tubular workpiece inner wall thin film deposition device further includes: a flow diversion structure and a gas collecting structure; the gas collecting structure is coated on the outside of the flexible heating element and the tubular workpiece, and trumpet-shaped flow diversion members are respectively provided at both ends of the gas collecting structure; the flow diversion structure is supported on the inner walls on both sides of the connection part between the discharge pipeline and the reaction chamber, and is used to divert the airflow flowing in from the feed pipeline to the gas collecting structure.

[0011] In a second aspect, an embodiment of the present invention further provides a method for depositing a thin film on the inner wall of a tubular workpiece. Based on the device for depositing a thin film on the inner wall of a tubular workpiece as described in the first aspect, the deposition method comprises:

[0012] S100, wrapping a flexible heating element on the outside of the tubular workpiece;

[0013] S200, placing the tubular workpiece on a supporting device of the reaction chamber;

[0014] S300, the reaction chamber is sealed and evacuated, reaction materials are introduced into the reaction chamber, and the flexible heating element is powered on and a corresponding temperature value is set;

[0015] S400, after the coating work is completed, the tubular workpiece is removed and the flexible heating element is recovered.

[0016] Optionally, in step S300, powering on the flexible heating element and setting a corresponding temperature value includes:

[0017] S310, preheating the first end heating section and the third end heating section, and the heating temperature of the middle second heating section is the calculated heating temperature;

[0018] S320, then heat the first end heating segment, N second heating segments and the third end heating segment at the same time, but the heating temperatures of the N second heating segments are lower than the heating temperatures of the first end heating segment and the third end heating segment; the heating temperatures of the first end heating segment, N second heating segments and the third end heating segment are the calculated heating temperatures; wherein the preheating temperature of the first end heating segment and the third end heating segment in S310 is higher than the heating temperatures of the first end heating segment and the third end heating segment in S320.

[0019] Optionally, in step S300, introducing reaction materials into the reaction chamber includes:

[0020] The actual amount of the reaction gas introduced into the reaction chamber is 1%-50% more than the theoretical amount.

[0021] Optionally, in step S310, the preheating temperature of the first end heating section and the third end heating section is 50-70° C., and the diameter of the tubular workpiece does not exceed 20 mm.

[0022] Optionally, the calculated heating temperature is obtained by the following formula: deposited film thickness Hi = k1-k2×Ti-k3×Li+k4×Ti×Li; k1: 52-55, k2: 0.79-1.1, k3: 2.6-4.2, k4: 0.02-0.08; half of the tubular workpiece is divided into i sections, specifically, the number of sections i is obtained by rounding the value after half of the length of the tubular workpiece divided by 2, i is an integer greater than or equal to 0, and the tube depth Li ranges from an even number between 0cm and half of the length of the tubular workpiece, in cm, including 0cm, for example, 0cm, 2cm, 4cm; the deposited film thickness H is the thickness of the thin film deposited on the inner wall of the target tubular workpiece The unit of thickness is μm; the calculated heating temperature corresponding to the first end heating section and the third end heating section is: (T0+T1) / 2 or T0; wherein T0 is the heating temperature of the first section in the half tubular workpiece, T1 is the heating temperature of the second section in the half tubular workpiece, and the adjacent first and second sections in the half tubular workpiece are close to the pipe mouth, as a high-temperature heating zone, corresponding to the first end heating section or the third end heating section, the temperature of the first end heating section and the third end heating section is the heating temperature T0 of the first section, or the average value of the first and second sections (T0+T1) / 2; the calculated heating temperature corresponding to the N second heating sections is: Ti, wherein i is an integer greater than 1. The embodiment of the present invention has at least the following technical effects:

[0023] The device and method for depositing a thin film on the inner wall of a tubular workpiece provided in the embodiments of the present invention wrap the tubular workpiece with a flexible heating element so that the heating body and the tubular workpiece are tightly fitted together without a gap for heating. The heating body wraps the tube body and heats it more evenly, with good heat conduction effect, which is beneficial to the uniform deposition of the thin film on the inner wall of the tube. At the same time, it is supported by the flexible heating element on the outer layer, has good thermal insulation properties, which is beneficial to improving the thermal utilization efficiency of the heating body, and is isolated from the supporting device to reduce the thermal influence of the supporting device, which is beneficial to improving the uniform deposition of the film. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 A schematic diagram of the overall structure of a thin film deposition device for the inner wall of a tubular workpiece provided by an embodiment of the present invention;

[0026] Figure 2 A schematic structural diagram of a tubular workpiece and a flexible heating element in a device for depositing a thin film on the inner wall of a tubular workpiece provided by an embodiment of the present invention;

[0027] Figure 3 A schematic flow chart of a method for depositing a thin film on the inner wall of a tubular workpiece provided in an embodiment of the present invention.

[0028] Icons: 100-reaction chamber; 200-feeding pipeline; 300-discharge pipeline; 400-support device; 500-tubular workpiece; 600-flexible heating element; 600a-first end heating section; 600b-second heating section; 600c-third end heating section; 610-tightening mouth; 700-flow diversion structure; 800-gas collection structure. DETAILED DESCRIPTION

[0029] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] Those skilled in the art will understand that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art in the field to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless specifically defined as here.

[0031] Those skilled in the art will appreciate that, unless otherwise stated, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. The term "and / or" used herein includes all or any unit and all combinations of one or more associated listed items.

[0032] Combination Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a thin film deposition device for the inner wall of a tubular workpiece 500, comprising: a deposition chamber; the deposition chamber comprises a reaction chamber 100, a feed pipeline 200 and a discharge pipeline 300, the feed pipeline 200 and the discharge pipeline 300 are relatively arranged on both sides of the reaction chamber 100, the feed pipeline 200 is used to introduce reaction materials (for example: polyparaxylene), and the discharge pipeline 300 is used to discharge waste gas after the reaction or incompletely reacted materials.

[0033] A support device 400 is provided in the reaction chamber 100, on which a tubular workpiece 500 to be plated is placed, and the outer wall of the tubular workpiece 500 is covered with a flexible heating element 600, and a heating body is distributed inside the flexible heating element 600 to be plated, which is used to heat the tubular workpiece 500 during the thin film deposition process. The lead wire of the heating body is led out from a window reserved in the reaction chamber 100 to facilitate electrical connection with an external power source.

[0034] Conventional heating methods for thin film deposition on tubular workpieces, for example, are performed by setting a tubular heating body and installing the tubular workpiece inside. However, it is difficult to center the workpiece, resulting in large heating deviation of the tubular workpiece and low deposition uniformity. For example, heating by a heating body outside the tube set at the upper or lower part also results in uneven heating inside the tube and low deposition uniformity. The thin film deposition device on the inner wall of the tubular workpiece 500 provided by the embodiment of the present invention wraps the tubular workpiece 500 with a flexible heating element 600, so that the heating element and the tubular workpiece 500 are tightly fitted together without a gap for heating. The heating element wraps the tube body for more uniform heating, and the heat conduction effect is good, which is conducive to the uniform deposition of the thin film on the inner wall of the tube. At the same time, it is supported by the outer layer of the flexible heating element 600, which has good thermal insulation properties, which is conducive to improving the thermal utilization efficiency of the heating element, and is isolated from the support device 400 to reduce the thermal influence of the support device 400, which is conducive to improving the uniform deposition of the film.

[0035] In some embodiments, the flexible heating element 600 includes cotton cloth, and the heating body is a heat conductor made of graphene material, and the heating body is distributed in the cotton cloth. For example, the flexible heating element 600 is a cotton cloth strip or a cotton cloth sleeve, and the cotton cloth strip can be wrapped around the outer surface of the tubular workpiece 500 for coating, and the cotton cloth sleeve can be directly mounted on the outer surface of the tubular workpiece 500 for coating due to its certain elasticity.

[0036] Specifically, the cotton cloth has a good heat preservation effect, which is mainly due to its structural and material characteristics, that is, the cotton cloth is woven from cotton yarn and has porosity and air pockets. These structural characteristics enable the cotton cloth to effectively slow down the loss of heat. The air pockets in the cotton cloth are poor conductors of heat, which helps to maintain the temperature of the tubular workpiece 500. In addition, since the cotton cloth has strong deformability and strong tensile strength, it can provide more effective protection for the graphene heating body, and the heating body is more durable.

[0037] In some embodiments, continue to refer to Figure 2 The flexible heating element 600 completely covers the tubular workpiece 500, and tightening openings 610 are respectively provided at both ends of the flexible heating element 600. The diameter of the tightening opening 610 accounts for 90% to 95% of the inner diameter of the tubular workpiece 500, that is, the size of the tightening opening 610 is slightly smaller than the inner diameter of the tubular workpiece 500, which will not affect the heating efficiency.

[0038] In this embodiment, the tube mouth is tightened at both ends to prevent the flexible heating element 600 from shifting due to thermal expansion and contraction, which is beneficial to maintaining a stable thermal field; and at the tightening mouth 610, the tube mouth is heated from the sides of both ends of the tube mouth to increase the heat on both ends of the tube, which is beneficial to making the temperature of both ends of the tube higher, forming a high-temperature section with a relatively high temperature that is beneficial to reducing the thickness of the deposited film at the tube mouth. Under the condition that the deposition pressure does not change, for the tubular workpiece 500 with a small aperture and a long size, the closer to the tube mouth, the higher the concentration of the reaction material, and the thicker the final deposition thickness; the farther from the tube mouth and the closer to the center of the tube, the lower the concentration of the reaction material, and the thinner the final deposition thickness. However, under the action of the flexible heating element 600, the temperature is transferred to the inner wall of the tube through the tube body, and the higher temperature generated at the tube mouth effectively suppresses the deposition rate of the film layer. The effects of relatively high temperature and relatively low temperature at the center of the long tube on the deposition rate of the film layer are opposite. Therefore, under the influence of the temperature gradient, the overall film thickness will reach a balanced state, and the inner wall of the tube from the tube mouth to the center of the tube will obtain a uniform film layer; since the two end surfaces of the tubular workpiece 500 will cause the reaction materials to be deposited here too early, the deposition of gas at the end will be aggravated, thereby causing the local thickness to increase, this embodiment covers the end of the tube mouth with the tightening mouth 610 and extends it away from the inner wall of the tube, thereby avoiding premature deposition of gas and prompting the gas that first enters the tube mouth to stay away from the inner wall of the tube mouth, which is beneficial to reducing problems such as excessive deposition at the end of the tube mouth causing the film layer to be too thick.

[0039] Optionally, the tightening opening 610 is provided with an air flow hole, which is beneficial to improving the heating of the gas, reducing the obstruction to the flow of the gas, facilitating the gas to enter the tube, and avoiding the possibility of local turbulence.

[0040] In some embodiments, continue to refer to Figure 2 The flexible heating element 600 includes a first end heating segment 600a, N second heating segments 600b and a third end heating segment 600c which are arranged in sequence. The three heating segments can be heated and controlled separately. The heating temperature of the second heating segment 600b is lower than the heating temperatures of the first end heating segment 600a and the third end heating segment 600c. The heating temperatures of the first end heating segment 600a and the third end heating segment 600c are the same or close. N is an integer greater than 1.

[0041] In this embodiment, the flexible heating element 600 is deheated in sections, and the overall heating temperature gradient is from high temperature to low temperature and then to high temperature. When the deposition pressure does not change, for the tubular workpiece 500 with a small aperture and a long length, the closer to the pipe mouth, the higher the concentration of monomer toluene gas, and the thicker the final deposition thickness; the farther from the pipe mouth and the closer to the center, the lower the concentration of monomer toluene gas, and the thinner the final deposition thickness; however, under the action of the heating cloth, the temperature is transmitted to the inner wall of the pipe through the pipe body, and the high temperature of the pipe mouth effectively suppresses the deposition rate of the film layer, while in the relatively high temperature section, the effect of the low temperature on the deposition rate of the film layer is opposite. Therefore, under the influence of the temperature gradient, the overall film thickness will reach a balanced state, so that a relatively uniform thin film layer is finally deposited on the inner wall of the pipe.

[0042] Optionally, the heating temperature of the N second heating sections 600b is at least 2°C lower than the heating temperature of the first end heating section 600a and the third end heating section 600c, preferably 5°C~100°C. By controlling the temperature difference appropriately, the uniformity of the film thickness inside the long tubular workpiece 500 can be improved.

[0043] In some embodiments, the thin film deposition apparatus for the inner wall of the tubular workpiece 500 further includes: a flow diversion structure 700 and a gas collection structure 800 .

[0044] Specifically, the gas collecting structure 800 is coated on the outside of the flexible heating element 600 and the tubular workpiece 500, and trumpet-shaped guide members are respectively provided at both ends of the gas collecting structure 800. The trumpet-shaped guide member is equivalent to a layer of air outside the flexible heating element to isolate the airflow outside the tube, which is conducive to the entry of the airflow inside the tube, so as to improve the uniformity of the film thickness when the airflow enters deeper into the tube.

[0045] Optionally, the middle of the trumpet-shaped guide member is a mounting portion (with a hollow structure in the middle), and both ends are trumpet-shaped expansion portions, and the smaller end of the trumpet-shaped expansion portion is connected to the mounting portion. The trumpet-shaped guide member is divided into two parts with the same structure along the center line, so that the tubular workpiece 500 coated with the flexible heating element 600 is conveniently surrounded by the mounting portion. The mounting portion can be fixed by a support member, so as to support the mounting portion at a preset position of the reaction chamber 100, so that the trumpet-shaped guide member near one end of the feed pipeline is aligned with the feed port, and the trumpet-shaped guide member near one end of the discharge pipeline is aligned with the discharge port.

[0046] Optionally, the trumpet-shaped flow guide may be merely a trumpet-shaped outward expansion structure installed at both ends of the tubular workpiece 500, with the smaller end of the trumpet-shaped outward expansion structure aligned with the pipe mouth of the tubular workpiece 500 and fixed by a support member, thereby supporting the trumpet-shaped outward expansion structure at a predetermined position of the reaction chamber 100, so that the trumpet-shaped flow guide near one end of the feed pipeline is aligned with the feed port, and the trumpet-shaped flow guide near one end of the discharge pipeline is aligned with the discharge port.

[0047] Further, the flow diversion structure 700 is supported on the inner walls on both sides of the connection between the discharge pipeline 300 and the reaction chamber 100, and is used to divert the gas flow flowing in from the feed pipeline 200 to the gas collection structure 800. Optionally, the flow diversion structure 700 has an arc-shaped flow guide groove, and the inlet size of the arc-shaped flow guide groove is larger, the outlet size is smaller, and the inlet to the outlet is gradually reduced, which is convenient for the swirling diversion of the gas flow. The arc-shaped flow guide groove is fixed to the inner wall of the reaction chamber 100.

[0048] In the present embodiment, the trumpet-shaped guide piece realizes the gas flow to be converged and diverted to the pipe mouth with reduced loss, reduces the energy loss of the gas flow hitting the inner wall of the furnace body, and reduces the airflow path of the gas returning after hitting the inner wall of the furnace, thereby increasing the power of the gas away from the gas inlet to enter the pipe. At the same time, by setting a gas collecting structure 800 with a tapered trumpet mouth, the large end of the trumpet mouth can expand the collection of gas entering the pipe (originally only the gas of the size of the pipe mouth enters the pipe), and the small end corresponds to the pipe mouth. Through the tapered structure, the flow rate of the gas entering the pipe can be increased, and the power of the gas flow entering the pipe is enhanced, so as to increase the depth of the gas entering the pipe, which is beneficial to improving the gas film formation deep in the pipe and improving the uniformity of the film formation on the inner wall of the pipe.

[0049] Based on the same inventive concept, Figure 3 As shown, an embodiment of the present invention further provides a method for depositing a thin film on the inner wall of a tubular workpiece. Based on the thin film deposition on the inner wall of a tubular workpiece as described in the above embodiment, the deposition method comprises:

[0050] S100, wrapping a flexible heating element on the outside of the tubular workpiece.

[0051] Specifically, by winding the flexible heating element on the outer surface of the tubular workpiece, it is beneficial for the film to be deposited on the inner wall of the tubular workpiece. Optionally, the flexible heating element can be a flexible heating strip or a flexible heating sleeve.

[0052] S200, placing the tubular workpiece on a supporting device of the reaction chamber.

[0053] Specifically, the tubular workpiece coated with the flexible heating element is placed on a supporting device, which can increase the support of the tubular workpiece and make the axis of the tubular workpiece parallel or substantially parallel to the axes of the feed pipeline and the discharge pipeline, thereby facilitating better airflow into the interior of the tubular workpiece.

[0054] S300, the reaction chamber is sealed and evacuated, reaction materials are introduced into the reaction chamber, and the flexible heating element is powered on and a corresponding temperature value is set.

[0055] Specifically, when the vacuum degree reaches 6-12mTorr, the raw material is heated and gasified to become xylene gas. The steam is cracked at high temperature to form monomer toluene gas, which is transported to the deposition chamber through a pipeline. Since a tubular workpiece to be processed is placed in the reaction chamber, the monomer toluene gas continuously flows into the tube. In order to improve the thin film deposition effect inside the tubular workpiece, the flexible heating element needs to be electrically heated to increase the temperature of the tubular workpiece, which is beneficial to improving the thin film deposition effect on the inner wall of the workpiece.

[0056] S400, after the coating work is completed, the tubular workpiece is removed and the flexible heating element is recovered.

[0057] Specifically, the flexible heating element is made of conventional cotton cloth plus graphene material. The graphene material has fast heat conduction, which is beneficial to improving the heating efficiency and can be used repeatedly.

[0058] In some embodiments, in step S300, the flexible heating element is powered on and a corresponding temperature value is set, including:

[0059] S310, firstly, the temperature of the first end heating section and the third end heating section is increased for preheating, and the heating temperature of the middle N second heating sections is the calculated heating temperature.

[0060] S320, then heat the first end heating segment, N second heating segments and the third end heating segment at the same time, but the heating temperatures of the N second heating segments are lower than the heating temperatures of the first heating segment and the third heating segment; the heating temperatures of the first end heating segment, N second heating segments and the third end heating segment are the calculated heating temperatures; wherein, the preheating temperature of the first end heating segment and the third end heating segment in S310 is higher than the heating temperatures of the first end heating segment and the third end heating segment in S320, and the deposition time is 3-10 seconds.

[0061] Specifically, optionally, in S310, the first end heating section and the third end heating section are preheated at a preheating temperature of 50-70° C., and the diameter of the tubular workpiece is less than 20 mm.

[0062] Step S310 is the pre-deposition stage at the center of the tubular workpiece. In this stage, the temperature of the first end heating section and the third end heating section is increased for pre-heating. The pre-heating temperature is relatively high, higher than the temperature of the inner wall of the thin film deposition tube, and the deposited film is not easy to be deposited at the tube mouth. Thus, the driving force for the raw material gas to enter the deep part of the tube from the port is increased, so that more raw material gas can enter the deep part of the tube for pre-deposition and film formation, which is beneficial to reduce the deviation of the film thickness between the tube mouth and the deep part of the tube (such as the center and vicinity of the tube length), and improve the uniformity of thin film deposition in the length direction of the tubular workpiece.

[0063] In step S320, the heating temperatures of the first end heating section and the third end heating section are lowered, and the heating temperatures calculated by calculating the film thickness of the first end heating section, the N second heating sections, and the third end heating section are precisely heated and controlled, so as to improve the uniformity of thin film deposition in the length direction of the tubular workpiece. Understandably, since the length of the tubular workpiece is long, although the difficulty of the raw material gas entering the tube depth is improved, it is still relatively difficult for the same raw material gas to enter the tube mouth. Improving the uniformity of thin film deposition in the length direction of the tubular workpiece mainly refers to reducing the deviation of the thin film deposition thickness at the tube mouth and the center, and avoiding the situation where the film cannot be deposited deep into the tube.

[0064] Optionally, the heating temperature is calculated by the following formula: i =k1-k2×T i -k3×L i +k4×T i ×L i ; k1: 52-55, k2: 0.79-1.1, k3: 2.6-4.2, k4: 0.02-0.08;

[0065] Divide half of the tubular workpiece into i segments, specifically, half of the length of the tubular workpiece divided by 2, and then round the value to obtain the segment number i, i is an integer greater than or equal to 0, and the tube depth L iThe value range is: an even number between 0cm and half the length of the tubular workpiece, in cm, including 0cm, for example, 0cm, 2cm, 4cm; the deposited film thickness H is the deposited film thickness of the inner wall of the target tubular workpiece, in μm; the calculated heating temperature corresponding to the first end heating section and the third end heating section is: (T0+T1) / 2 or T0; wherein T0 is the heating temperature of the first section in half of the tubular workpiece, T1 is the heating temperature of the second section in half of the tubular workpiece, and the adjacent first and second sections in half of the tubular workpiece are close to the pipe mouth, as a high-temperature heating zone, corresponding to the first end heating section or the third end heating section, and the temperature of the first end heating section and the third end heating section is the heating temperature T0 of the first section, or the average value of the first and second sections (T0+T1) / 2; the calculated heating temperature corresponding to the N second heating sections is: T i , where i is an integer greater than 1.

[0066] For example: the length of the tubular workpiece is 20cm, half of the length of the tubular workpiece is 10cm, which is divided into 5 sections, i=0, 1, 2, 3, 4; the range of the tube depth Li is an even number between 0 and 10cm, that is, L0 is 0cm, L1 is 2cm, L2 is 4cm, L3 is 8cm, and L4 is 10cm; the deposited film thickness H is the target tube workpiece inner wall film deposition thickness, which can be obtained according to historical data, process requirements, etc. After the deposited film thickness H is determined as the target tube workpiece inner wall film deposition thickness, the above formula can be used to calculate the calculated heating temperatures T0, T1, T2, T3, and T4 corresponding to different tube depths Li, so as to obtain a better multi-section heating temperature to achieve the target film thickness, realize precise temperature control, and help improve the uniformity of film formation. Since the temperature drop at the pipe mouth is significantly smaller, the temperature deviation between adjacent sections at the pipe mouth is small, and the temperature deviation is large at a deeper point in the pipe. In order to improve the temperature control accuracy, the high-temperature zone at the pipe mouth selects two adjacent sections close to the pipe mouth as a high-temperature heating zone, and each of the remaining sections (N) is used as a separate heating zone (i.e., N second heating sections). The calculated heating temperature corresponding to the first end heating section and the third end heating section is: (T0+T1) / 2 or T0; the calculated heating temperature corresponding to the N second heating sections is: T i , where i is an integer greater than 1 and is divided into 5 segments, i=0,1,2,3,4, and the corresponding heating temperatures are T2, T3, and T4.

[0067] In some embodiments, in step S300, introducing reaction materials into the reaction chamber includes:

[0068] The actual amount of the reaction material introduced into the reaction chamber is 1%-50% more than the theoretical amount.

[0069] In this embodiment, by increasing the amount of gas added, it is beneficial to promote film formation inside the long tube diameter, reduce defects such as small film thickness or no film formation on the inner wall in the middle of the long tube caused by insufficient gas usage, and improve the film quality.

[0070] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0071] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0072] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific conditions. In the description of this specification, specific features, structures, materials or characteristics can be combined in a suitable manner in any one or more embodiments or examples.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A thin film deposition device for the inner wall of a tubular workpiece, characterized in that: include: A deposition chamber, the deposition chamber comprising a reaction chamber, a feed pipeline and a discharge pipeline are arranged on two sides of the reaction chamber, and a support device is arranged in the reaction chamber, and the support device is used to place the tubular workpiece to be plated; The outer wall of the tubular workpiece is covered with a flexible heating element, and a heating body is distributed inside the flexible heating element to be plated, which is used to heat the tubular workpiece during the thin film deposition process; the flexible heating element completely covers the tubular workpiece, and tightening openings are respectively provided at both ends of the flexible heating element; the flexible heating element includes a first end heating segment, N second heating segments and a third end heating segment which are arranged in sequence, the heating temperature of the second heating segment is lower than the heating temperature of the first end heating segment and the third end heating segment, and the heating temperature of the first end heating segment and the third end heating segment are the same; wherein N is an integer greater than 1; A flow diversion structure and a gas collection structure; the gas collection structure is coated on the outside of the flexible heating element and the tubular workpiece, and trumpet-shaped flow diversion members are respectively provided at both ends of the gas collection structure; the flow diversion structure is supported on the inner walls on both sides of the connection part between the discharge pipeline and the reaction chamber, and is used to divert the gas flow flowing in from the feed pipeline to the gas collection structure.

2. The thin film deposition device for inner wall of tubular workpiece according to claim 1, characterized in that: The flexible heating element comprises cotton cloth, the heating body is a heat conductor made of graphene material, and the heating body is distributed in the cotton cloth.

3. The device for depositing a thin film on the inner wall of a tubular workpiece according to claim 1 or 2, characterized in that: The diameter of the tightening opening accounts for 90% to 95% of the inner diameter of the tubular workpiece.

4. The device for depositing a thin film on the inner wall of a tubular workpiece according to claim 3, characterized in that: The tightening opening is provided with an air flow passage hole.

5. The device for depositing a thin film on the inner wall of a tubular workpiece according to claim 1, characterized in that: The heating temperature of the second heating section is at least 2° C. lower than the heating temperatures of the first end heating section and the third end heating section.

6. A method for depositing a thin film on the inner wall of a tubular workpiece, based on the device for depositing a thin film on the inner wall of a tubular workpiece as claimed in any one of claims 1 to 5, characterized in that: The method comprises: S100, wrapping a flexible heating element on the outside of the tubular workpiece; S200, placing the tubular workpiece on a supporting device of the reaction chamber; S300, the reaction chamber is sealed and evacuated, reaction materials are introduced into the reaction chamber, and the flexible heating element is powered on and a corresponding temperature value is set; S400, after the coating work is completed, the tubular workpiece is removed and the flexible heating element is recovered; In step S300, the step of powering on the flexible heating element and setting a corresponding temperature value includes: S310, preheating the first end heating section and the third end heating section, and the heating temperatures of the N second heating sections in the middle are the calculated heating temperatures; S320, then heat the first end heating segment, N second heating segments and the third end heating segment at the same time, but the heating temperatures of the N second heating segments are lower than the heating temperatures of the first end heating segment and the third end heating segment; the heating temperatures of the first end heating segment, N second heating segments and the third end heating segment are the calculated heating temperatures; wherein the preheating temperature of the first end heating segment and the third end heating segment in S310 is higher than the heating temperatures of the first end heating segment and the third end heating segment in S320.

7. The method for depositing a thin film on the inner wall of a tubular workpiece according to claim 6, characterized in that: In step S300, the step of introducing reaction materials into the reaction chamber includes: The actual amount of the reaction gas introduced into the reaction chamber is 1%-50% more than the theoretical amount.

8. The method for depositing a thin film on the inner wall of a tubular workpiece according to claim 6, characterized in that: In S310, the first end heating section and the third end heating section are preheated at a preheating temperature of 50-70° C., and the diameter of the tubular workpiece does not exceed 20 mm.

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