Coating workpiece temperature control structure based on sliding interface heat conduction

Abstract

The invention relates to the technical field of thin film deposition, in particular to a coating workpiece temperature control structure based on sliding interface heat conduction, which comprises a base, a rotation shaft, a workpiece base, an inlet pipeline and an outlet pipeline, the rotation shaft is fixed on the base, and the interior of the rotation shaft is of a hollow structure; the workpiece base sleeves the periphery of the rotation shaft and is in sliding contact with the rotation shaft; one end of the inlet pipeline is connected with an external heat pump or refrigerator, and the other end penetrates through the base and enters the rotation shaft; one end of the outlet pipeline is arranged in the rotation shaft, and the other end penetrates through the base to be communicated with the outside. In the coating process, based on the sliding interface, the temperature of the workpiece can be independently adjusted in a heat conduction mode, adjustment of other deposition parameters does not affect one another, the workpiece temperature at the room temperature and the deep low temperature can be obtained, the complex relation which is difficult to predict among the temperature, the bias voltage and the coating power is eliminated, and the coating efficiency is improved. And the stability of the technological process is improved.

Description

Technical Field

[0001] The present application relates to the technical field of thin film deposition, and in particular to a temperature control structure for a film-coated workpiece based on heat conduction at a sliding interface. Background Art

[0002] Temperature is one of the important process parameters in the workpiece coating process and it is also a complex issue.

[0003] At present, in situations where the temperature of the workpiece needs to be increased, the general method is to use a radiation heater to "bake" the workpiece to heat it. The method is simple and effective, but there are the following problems: 1. The radiation power of the heater, the radiation absorption coefficient of the workpiece surface, the heating effect of the deposition jet, the heat conduction of the workpiece table structure and other factors will affect the temperature of the workpiece, and the final temperature is determined by the thermal balance of the above factors; however, these factors often change with the process parameters and the deposition process. For example, during the film deposition process, if the workpiece needs to be biased, the bombardment power of the deposition jet will also heat the workpiece; during the deposition process, the workpiece surface is gradually covered by the film, and the absorption coefficient of the heater radiation will also change, causing the workpiece temperature to deviate from the preset temperature; because the workpiece temperature and other factors are intertwined and difficult to control independently, the working conditions become complicated, and unqualified products often appear for unknown reasons. The coating process often relies more on exploration and experience, and any parameters cannot be easily adjusted, and it is difficult to quickly optimize the process. In this case, not only the cost is greatly increased, but it is even a question of the success or failure of the process. 2. It is impossible to obtain room temperature and lower workpiece temperature (which is often necessary). According to the blackbody radiation law, the radiation power is proportional to the fourth power of the temperature. When the temperature is low, the radiation heat transfer is extremely weak and cannot affect the temperature of the workpiece. Therefore, radiation heat transfer cannot be used to obtain low temperatures.

[0004] Therefore, radiation heating is not ideal and its application has limitations. Using heat conduction heat exchange, such as using a water-cooled (or oil-heated) base and mounting the workpiece directly on the base, can in principle get rid of the problems caused by radiation heat exchange. However, it has not been widely used in industrial equipment. This is because the thickness uniformity, physical property uniformity, cost, and production capacity of the film are rigid indicators for industrial equipment. The workpiece must be in revolution + rotation to achieve uniformity. To achieve conduction heat exchange, the heat exchange medium (such as water, oil, refrigerant, etc.) needs to be piped to the workpiece base (heat sink, the workpiece is mounted on this base) in the vacuum. However, if the base is rotating, it is difficult to connect the fixed pipe to the rotating base, and how to achieve independent regulation of the workpiece temperature is also a difficulty. Summary of the invention

[0005] The present application provides a coating workpiece temperature control structure based on sliding interface heat conduction, which eliminates the complex and unpredictable interactions between the workpiece temperature and bias voltage, deposition power, and workpiece radiation absorption coefficient during the coating process, so that the workpiece temperature can remain stable.

[0006] In order to achieve the above-mentioned purpose, the present application provides a temperature control structure for a coated workpiece based on heat conduction at a sliding interface, comprising a base, a rotating shaft, a workpiece base, an inlet pipe and an outlet pipe, wherein: the rotating shaft is fixed on the base and has a hollow structure inside; the workpiece base is sleeved on the periphery of the rotating shaft and is in sliding contact with the rotating shaft; one end of the inlet pipe is connected to an external heat pump or refrigerator, and the other end passes through the base into the interior of the rotating shaft for the entry of heat exchange medium; one end of the outlet pipe is arranged inside the rotating shaft, and the other end passes through the base to communicate with the outside world for the discharge of heat exchange medium; in the internal area of ​​the rotating shaft, the length of the inlet pipe is greater than the length of the outlet pipe.

[0007] Furthermore, the workpiece base is divided into a first half base and a second half base as a whole, and the first half base and the second half base are connected by spring tensioning.

[0008] Furthermore, a thin layer of nano-slurry is sprayed between the workpiece base and the rotating shaft.

[0009] Furthermore, the heat exchange medium is water or oil.

[0010] Furthermore, a rotation drive motor is arranged on the outer side of the workpiece base to drive the workpiece base to rotate.

[0011] Furthermore, before coating, multiple groups of coating workpiece temperature control structures are combined together and placed in a vacuum environment, and the base of each group of coating workpiece temperature control structures is connected to the orbiting spindle.

[0012] Furthermore, during the coating process, the base revolves under the drive of the revolving spindle, and the workpiece base rotates under the drive of the rotating shaft.

[0013] The present invention provides a coating workpiece temperature control structure based on sliding interface heat conduction, which has the following beneficial effects:

[0014] During the coating process, the present application uses heat conduction based on the sliding interface to independently adjust the temperature of the workpiece without affecting the adjustment of other deposition parameters, and can obtain room temperature and deep low temperature workpiece temperatures, eliminating the unpredictable and complex relationship between temperature and bias voltage and coating power, thereby improving the stability of the process. The heat exchange cycle has a strong load capacity and can withstand higher thermal power, making the temperature of the workpiece more stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings constituting a part of this application are used to provide a further understanding of this application, so that other features, purposes and advantages of this application become more obvious. The schematic embodiment drawings and their descriptions of this application are used to explain this application and do not constitute an improper limitation on this application. In the drawings:

[0016] Figure 1 It is a schematic diagram of a coating workpiece temperature control structure based on sliding interface heat conduction provided according to an embodiment of the present application;

[0017] Figure 2 is a schematic diagram of a laser arc coating device provided according to an embodiment of the present application;

[0018] In the figure: 1-base, 2-rotation axis, 3-workpiece base, 4-inlet pipe, 5-outlet pipe, 6-heat exchange medium, 7-laser, 8-laser scanning galvanometer, 9-vacuum chamber cavity, 10-arc electrode, 11-vacuum unit, 12-control unit, 13-circular base, 14-revolution spindle, 15-deposition jet. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0020] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0021] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0022] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0023] In addition, the term "plurality" shall mean two or more.

[0024] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0025] like Figure 1 As shown, the present application provides a coating workpiece temperature control structure based on sliding interface heat conduction, including a base 1, a rotating shaft 2, a workpiece base 3, an inlet pipe 4 and an outlet pipe 5, wherein: the rotating shaft 2 is fixed on the base 1, and the interior is a hollow structure; the workpiece base 3 is sleeved on the periphery of the rotating shaft 2 and is in sliding contact with the rotating shaft 2; one end of the inlet pipe 4 is connected to an external heat pump or refrigerator, and the other end passes through the base 1 to enter the interior of the rotating shaft 2 for the entry of a heat exchange medium 6; one end of the outlet pipe 5 is arranged inside the rotating shaft 2, and the other end passes through the base 1 to communicate with the outside world for the discharge of the heat exchange medium 6; in the internal area of ​​the rotating shaft 2, the length of the inlet pipe 4 is greater than the length of the outlet pipe 5.

[0026] Specifically, the coating workpiece temperature control structure based on sliding interface heat conduction provided in the embodiment of the present application is coordinated through a workpiece base 3 and a rotating shaft 2 serving as a heat sink / heat source. The workpiece base 3 is entirely sleeved on the rotating shaft 2 and is in sliding contact therewith. The workpiece is entirely mounted on the workpiece base 3, and the interior of the rotating shaft 2 is a hollow structure. A heat pump or a refrigerator passes a heat exchange medium 6 into the interior of the rotating shaft 2 through an inlet pipe 4. The heat exchange medium 6 will perform a heat exchange cycle inside the rotating shaft 2 and be discharged through an outlet pipe 5, thereby injecting heat into or taking away heat from the interior of the rotating shaft 2, so as to achieve the purpose of controlling the temperature of the rotating shaft 2 at a set value; and the workpiece base 3 sleeved on the rotating shaft 2 can drive the workpiece to rotate, and at the same time exchange heat with the rotating shaft 2 through a sliding interface, thereby finally realizing heat exchange between the workpiece and the heat sink.

[0027] More specifically, the above description is the basic process of coating in the embodiment of the present application, but whether the structure based on the heat conduction of the sliding interface can be realized still needs to be quantitatively analyzed. Generally speaking, the two solid interfaces that slide against each other are not ideally smooth, and only the micro-protrusions on the surface contact each other when they contact each other. Therefore, the actual effective thermal contact area is much smaller than the apparent contact area, usually only 1% of the apparent contact area, which means that the interface thermal resistance has to be increased by 100 times, which seems to be unsuitable for heat exchange. However, from the perspective of the heat conduction path, the heat conduction length of the sliding interface (the root mean square value of the surface roughness) is very short, only in the micrometer range. A few micrometers below the interface, the surface heat conduction area is the same as the apparent area, so the thermal resistance value of the sliding interface is not large, which can be expressed by the following formula:

[0028]

[0029] Where k is the thermal conductivity of the sliding interface material, A e is the effective contact area of ​​the sliding surface, L is the length of the heat conduction path (root mean square roughness of the sliding interface), and P is the heat power input to the sliding interface; it can be seen from the above formula that under the commonly used coating process conditions (assuming that the workpiece is biased, the average bombardment power of the deposition jet 15 on the total area of ​​the workpiece base 3 is 5kW, the root mean square roughness Ra is 3.2μm, the thermal conductivity of 304 stainless steel material is 16.3W / m·K, and the effective thermal contact area A e is 2*10 -4 m 2(1 / 1000 apparent contact area), the temperature difference on both sides of the sliding interface is △T about 4.9℃; and the sliding interface can be sprayed with graphite or molybdenum disulfide nanopowder, the filling effect increases the effective contact area, further reduces the thermal resistance, and the temperature difference will be smaller; and in addition to the sliding interface, the heat conduction path between the heat exchange medium 6 flowing in the rotating shaft 2 and the workpiece is also very short, ensuring very small thermal resistance and the ability to withstand thermal power. In this way, from the above quantitative analysis results, the sliding interface heat conduction can carry enough thermal power, and the coating workpiece temperature control structure based on sliding interface heat conduction provided in the embodiment of the present application can reach the industrial use level and realize the temperature control of the coating workpiece.

[0030] Furthermore, the workpiece base 3 is divided into a first half base and a second half base, and the first half base and the second half base are connected by a spring. The workpiece base 3 is divided into two halves, and the two halves are tightly connected together by a spring and a pin to form a complete workpiece base 3, and the whole is sleeved on the periphery of the rotating shaft 2 and contacts the rotating shaft 2. By adjusting the tension of the spring, the contact pressure between the workpiece base 3 and the rotating shaft 2 can be fine-tuned.

[0031] Furthermore, a thin layer of nano-slurry is sprayed between the workpiece base 3 and the rotating shaft 2. A thin layer of nano-slurry of vacuum compatible materials such as sprayed graphite or molybdenum disulfide is sprayed between the workpiece base 3 and the rotating shaft 2, which can increase the area of ​​thermal contact and play a lubricating role.

[0032] Furthermore, the heat exchange medium 6 is water or oil. The heat exchange medium 6 is preferably water or oil. The heat pump or refrigerator passes the water or oil into the hollow structure inside the rotating shaft 2 through the inlet pipe 4. After the water or oil flows inside the rotating shaft 2 for heat exchange, it is discharged through the outlet pipe 5 below, thereby realizing the heat exchange cycle inside the rotating shaft 2, increasing the temperature of the rotating shaft 2 or cooling the rotating shaft 2, so that the temperature of the rotating shaft 2 is stably maintained within a set range.

[0033] Furthermore, a rotation drive motor is arranged outside the workpiece base 3 to drive the workpiece base 3 to rotate. The rotation drive motor is arranged outside the workpiece base 3 and connected to the rotation shaft 2 to drive the rotation of the rotation shaft 2, thereby driving the workpiece base 3 and the workpiece thereon to rotate together.

[0034] Furthermore, before coating, a plurality of sets of coating workpiece temperature control structures are combined together and placed in a vacuum environment, and the base 1 of each set of coating workpiece temperature control structures is connected to the orbiting spindle 14 .

[0035] Furthermore, during the coating process, the base 1 revolves under the drive of the revolution spindle 14 , and the workpiece base 3 rotates under the drive of the rotation shaft 2 .

[0036] Specifically, Figure 2 As shown, in actual coating applications, the coating workpiece temperature control structure based on sliding interface heat conduction provided in the embodiment of the present application can be applied to laser arc coating equipment. The laser arc coating as a whole includes a laser 7, a laser scanning galvanometer 8, a vacuum chamber cavity 9, an arc electrode 10, a vacuum unit 11 and a control unit 12, wherein the laser 7 and the laser scanning galvanometer 8 are arranged above the vacuum chamber cavity 9, and are used to connect with the control unit 12 to emit a deposition jet 15 to the thin film inside the vacuum chamber cavity 9; the vacuum unit 11 is arranged below the vacuum chamber cavity 9, and is connected with the control unit 12 to evacuate the vacuum chamber cavity 9; and a plurality of sets of coating workpiece temperature control structures are arranged inside the vacuum chamber cavity 9, and 10 rotating shafts 2 are evenly installed and distributed on the circular base 13 with the revolution main axis 14 as the center, and are connected to the arc electrode 10 on the central axis. The arc electrode 10 constitutes the layout structure of the radial deposition jet 15; a total inlet pipe and a total outlet pipe are arranged on the revolution main shaft 14 at the center of the circular base 13, the total inlet pipe is connected to the inlet pipe 4 in each rotating shaft 2, and is used to distribute the heat exchange medium 6 to each rotating shaft 2, and the total outlet pipe is connected to the outlet pipe 5 in each rotating shaft 2, and is used to merge the heat exchange medium 6 and export it to the vacuum chamber cavity 9 through the hollow revolution main shaft 14 on the circular base 13; the total inlet pipe and the total outlet pipe are fixed to the circular base 13 and can rotate therewith, and are connected to the ground fixed pipe through a rotating sealing joint to eliminate the transmission of the pipe revolution motion, and are connected to an external heat pump or refrigerator after the transmission is eliminated, and the rotating sealing joint is arranged outside the vacuum chamber cavity 9. During the coating process, even if there is a small leakage, it will not affect the vacuum chamber cavity 9.

[0037] More specifically, during film coating, multiple workpieces are placed on the workpiece base 3, and then the vacuum chamber cavity 9 is evacuated by the vacuum unit 11, and then the circular base 13 is driven by the revolution spindle 14 to revolve by the control unit 12, so that the workpiece and the workpiece base 3 are driven by the rotation axis 2 to rotate as a whole, and then the workpiece surface is irradiated by the laser 7, the laser scanning galvanometer 8 and the arc electrode 10 to achieve the deposition of the thin film; during the deposition of the thin film, the heat exchange medium 6 can be introduced into the inlet pipe 4 inside each rotation axis 2 through the total inlet pipe, and the heat exchange medium 6 is discharged through the total outlet pipe after flowing and exchanging heat in the rotation axis 2, so as to achieve the control and regulation of the temperature of each rotation axis 2. In this way, during the film coating process, not only the independent regulation of the workpiece temperature is achieved, and the regulation of other deposition parameters does not affect each other, but also the unpredictable complex relationship between temperature, bias voltage and coating power can be eliminated, and the stability of the process is improved, which is of great benefit to understanding the mechanism and law of thin film deposition, obtaining the best process parameters and reducing the cost of process exploration.

[0038] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A coating workpiece temperature control structure based on sliding interface heat conduction, characterized in that: It includes a base, a rotating shaft, a workpiece base, an inlet pipe and an outlet pipe, wherein: The rotating shaft is fixed on the base and has a hollow structure inside; The workpiece base is sleeved on the periphery of the rotating shaft and is in sliding contact with the rotating shaft; One end of the inlet pipe is connected to an external heat pump or refrigerator, and the other end passes through the base and enters the interior of the rotating shaft for the entry of heat exchange medium; One end of the outlet pipe is arranged inside the rotating shaft, and the other end passes through the base and communicates with the outside world, so as to discharge the heat exchange medium; In the inner region of the rotation shaft, the length of the inlet pipe is greater than the length of the outlet pipe.

2. The coating workpiece temperature control structure based on sliding interface heat conduction according to claim 1 is characterized in that: The workpiece base is divided into a first half base and a second half base as a whole, and the first half base and the second half base are connected by spring tensioning.

3. The coating workpiece temperature control structure based on sliding interface heat conduction according to claim 2 is characterized in that: A thin layer of nano slurry is sprayed between the workpiece base and the rotating shaft.

4. The coating workpiece temperature control structure based on sliding interface heat conduction according to claim 1 is characterized in that: The heat exchange medium is water or oil.

5. The coating workpiece temperature control structure based on sliding interface heat conduction according to claim 1 is characterized in that: A rotation driving motor is arranged on the outer side of the workpiece base, which is used to drive the workpiece base to rotate.

6. The coating workpiece temperature control structure based on sliding interface heat conduction according to claim 5 is characterized in that: Before coating, multiple sets of coating workpiece temperature control structures are combined together and placed in a vacuum environment, and the base of each set of coating workpiece temperature control structures is connected to the orbiting spindle.

7. The coating workpiece temperature control structure based on sliding interface heat conduction according to claim 6 is characterized in that: During the coating process, the base revolves under the drive of the revolving spindle, and the workpiece base rotates under the drive of the rotating shaft.

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