Liquid metal-based cleaning method and integrated cleaning and application apparatus

Abstract

The present invention provides a liquid metal-based cleaning method and an integrated cleaning and application device, which belongs to the field of thermal interface material operation technology. The method includes base cleaning and testing whether the cleaning is acceptable, the base cleaning includes one or more of plasma cleaning, inorganic cleaning agent cleaning, and organic cleaning agent cleaning, or any combination of the plasma cleaning, inorganic cleaning agent cleaning, and organic cleaning agent cleaning, and the testing whether the cleaning is acceptable is based on the diffusion area of ​​the organic reagent on the liquid metal base surface, and if the diffusion area meets a predetermined requirement, the cleaning is completed, and if the diffusion area does not meet the predetermined requirement, the base cleaning step is repeated, and the above-mentioned repetition continues until the diffusion area meets the predetermined requirement. The present invention cleans the base surface of the chip and the heat sink, etc., and fundamentally solves the problem of the liquid metal and the base not being wetted.

Description

[Technical field]

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] This application claims priority to a Chinese patent application filed with the China Patent Office on September 13, 2022, bearing application number CN202211111691.3 and entitled "LIQUID METAL-BASED CLEANING METHOD AND INTEGRATED APPARATUS FOR CLEANING AND APPLICATION," the entire contents of which are incorporated herein by reference.

[0002] The present invention is in the field of thermal interface material operations, and more particularly relates to an integrated apparatus for liquid metal-based cleaning and application. [Background technology]

[0003] Compared with traditional silicone grease, liquid metal has a large surface tension, so it is difficult to apply to the surface of the chip and the heat sink. If the application is poor, it will greatly affect the heat dissipation performance of the chip and cause product defects. At present, there are mainly two methods. One is to modify the liquid metal and increase the viscosity of the liquid metal at the expense of part of the thermal conductivity coefficient, thus reducing the difficulty of applying the liquid metal to the base to a certain extent. The other is to solve the problem of applying the liquid metal by applying it dozens of times, the principle of which is also similar to the modification treatment, and similarly sacrifices part of the thermal conductivity coefficient and shortens the service life of the liquid metal. Neither of the two methods can solve the wetting problem of the liquid metal and the base well, so we need to find a way to solve the wetting problem of the liquid metal and the base well, not reduce the performance of the liquid metal, and at the same time ensure the ease of operation and facilitate mass production.

[0004] Because liquid metal is an emerging industry, there is currently no integrated equipment in the market that can be applied to liquid metal base cleaning and liquid metal application, and the traditional solution is to use multiple devices with a single function in combination, which is disadvantageous to the widespread use in the industry.

[0005] The information disclosed in this Background is intended only to enhance the understanding of the general context of the present invention and should not be construed as an admission or in any manner suggesting that this information constitutes prior art well known to those skilled in the art. Summary of the Invention [Problem to be solved by the invention]

[0006] In order to solve the technical problems of the prior art in that the application of liquid metal is difficult and sacrifices part of the thermal conductivity coefficient of liquid metal, a liquid metal-based cleaning method and an integrated device for cleaning and application are provided. [Means for solving the problem]

[0007] The present invention is realized mainly by cleaning chips and heat sinks. Although chips and heat sinks look clean to the human eye, they are actually slightly dirty on the surface, and the dirt mainly contains organic and inorganic substances. If these two types of substances are removed by cleaning, the liquid metal will theoretically have good wettability to chips and heat sinks.

[0008] According to a first aspect of the present invention, there is provided a liquid metal based cleaning method, comprising a base cleaning and testing for passing the cleaning, the steps of which are as follows:

[0009] The base cleaning may include a plasma cleaning, and / or a cleaning with an inorganic cleaning agent, and / or a cleaning with an organic reagent, or any combination of the plasma cleaning, the cleaning with an inorganic cleaning agent, and the cleaning with an organic reagent; The inspection of whether the cleaning is passed is based on the spreading area of ​​the organic reagent on the liquid metal base surface, if the spreading area reaches the predetermined requirement, the cleaning is completed, if the spreading area does not reach the predetermined requirement, the base cleaning step is repeated, and so on until the spreading area reaches the predetermined requirement. Preferably, the predetermined requirement is that the maximum spreading area of ​​the organic reagent on the base surface after cleaning is 6.5 times or more than the area when dropped before cleaning, and the organic reagent is preferably anhydrous ethanol.

[0010] In some embodiments, the inorganic cleaning agent is one selected from a sodium bicarbonate solution, a low concentration strong acid solution, a high concentration weak acid solution, a low concentration strong alkaline solution, and a high concentration weak alkaline solution.

[0011] In some embodiments, the strong acid solution is one or more selected from dilute hydrochloric acid, dilute sulfuric acid, dilute nitric acid, hydrobromic acid, hydroiodic acid, phosphoric acid, permanganic acid; and / or the weak acid solution is selected from hydrofluoric acid and / or acetic acid; and / or the strong alkaline solution is one or more selected from sodium oxide, potassium hydroxide, and barium hydroxide; and / or the weak acid solution is selected from sodium bicarbonate and / or sodium carbonate.

[0012] In some embodiments, the organic reagent is one or more selected from alcohols, hydrocarbons, ethers, esters, and ketones.

[0013] In some embodiments, the organic reagent is one or more selected from ethanol, methanol, dipropylene glycol butyl ether, diethylene glycol butyl ether, hydrocarbon detergents, acetone, toluene, ethyl acetate, and ethyl ether.

[0014] JPEG2025501512000002.jpg149147

[0015] The above cleaning methods are one or a combination of cleaning methods, and the above methods may be selected according to actual needs.

[0016] In some embodiments, the inorganic cleaning agent is a sodium bicarbonate solution and the organic reagent is absolute ethanol.

[0017] According to a second aspect of the present invention, an integrated device for cleaning and applying liquid metal base is provided, which includes an accumulation table, on which a cleaning unit, a wiping unit, an application unit and an image sensor are attached, and the accumulation table is attached to a moving mechanism. The functions of cleaning, wiping and application are integrated into one device, and the image information is captured by the image sensor and sent to a control system to realize the movement and positioning of the device, and then the base is repeatedly washed and wiped according to a program, so that oil stains and the like on the surface of the base are completely removed by cleaning, and the base is directly applied after being cleaned, eliminating the intermediate transfer process and avoiding secondary contamination.

[0018] In some embodiments, the cleaning unit includes a number of cleaning devices, the wiping unit includes at least one wiping device, and the application unit includes at least one application device. Preferably, the cleaning device includes a plasma cleaner, a first spray head, and a second spray head, the first spray head containing the inorganic cleaning agent and the second spray head containing the organic cleaning agent.

[0019] A method for operating the integrated device, comprising the steps of: a base cleaning step in which the liquid metal base surface is repeatedly cleaned using any combination of the plasma cleaner, the first spray bed, and the second spray head, and the liquid metal base surface is wiped clean with the wiper after each cleaning step; A base inspection is performed by dropping the organic cleaning agent from the second spray head onto the liquid metal base surface, and judging whether the organic cleaning agent is passed or not based on the spreading area of ​​the organic agent on the liquid metal base surface. If the spreading area meets the predetermined requirement, the cleaning is completed; if the spreading area does not meet the predetermined requirement, the base cleaning step is repeated, and the repeat is continued until the spreading area meets the predetermined requirement; The method includes applying liquid metal to the liquid metal base, the method including controlling a liquid metal application device by a computer to apply liquid metal to the liquid metal base.

[0020] In some embodiments, the operating units of the cleaning device, wiping device and applicator device are all exposed outside the accumulation table and oriented perpendicular to the ground. The external mounting design is compatible with retrofitting to most conventional production lines.

[0021] In some embodiments, the cleaner and applicator devices each include a containment chamber for containing a cleaning fluid and liquid metal.

[0022] In some embodiments, the cleaning apparatus includes a plasma cleaner, a first spray head, and a second spray head, the first spray head containing a sodium bicarbonate solution and the second spray head containing anhydrous ethanol.

[0023] In some embodiments, the movement mechanism includes an X-direction slide table and a Z-direction slide table, and the accumulation table is movable left and right and up and down relative to each of the X-direction slide table and the Z-direction slide table.

[0024] In some embodiments, the moving mechanism further includes a Y-direction sliding table, and the accumulation table is movable back and forth relative to the Y-direction sliding table. By setting the X-direction sliding table, the Z-direction sliding table, and the Y-direction sliding table, the accumulation table is moved in three-dimensional space.

[0025] In some embodiments, the integrated apparatus further includes a first support frame and a second support frame, the first support frame fixedly connected to one end of the X-direction sliding table, and the second support frame fixedly connected to the other end of the X-direction sliding table.

[0026] In some embodiments, a connector is provided at the bottom of each of the first support frame and the second support frame, and the first support frame and the second support frame are fixed to a platform of a production line via the connector. Effect of the Invention

[0027] Compared with the prior art, the technical advantages achieved by the present invention are as follows: (1) Compared with the conventional solutions, the method and device of the present invention thoroughly cleans the base surfaces of the chip and heat sink, fundamentally solving the problem of the liquid metal not wetting the base, and allows the unmodified liquid metal solution to be quickly and uniformly applied to the base surfaces of the chip and heat sink, without loss of thermal conductivity of the liquid metal, and good contact between the liquid metal and the base of the chip and heat sink, without interruption by dirty film layers, and better heat dissipation effect. The good contact also alleviates the problem of the liquid metal sticking between the chip and heat sink and leaking due to the large surface tension, and if cleaning is not performed according to the device and method, or cleaning is not performed well, the liquid metal will easily leak out from between the chip and heat sink, resulting in ineffective heat dissipation. (2) The equipment of the present invention integrates base cleaning for liquid metal, inspection of cleaning effect, and application of liquid metal, and meets the automation needs of the liquid metal industry. The external installation design can be retrofitted to most traditional production lines, and can quickly realize the upgrade of traditional production lines. The design of many cleaning methods also makes it easy for manufacturers to select according to actual circumstances. [Brief description of the drawings]

[0028] [Figure 1]FIG. 2 is a structural schematic diagram of the present invention. [Diagram 2] 4 is a schematic diagram of the mechanisms of a first support frame and a second support frame. FIG. [Diagram 3] These are photographs of the test results of Experiment 1. [Figure 4] These are photographs of the test results of Experiment 2. [Diagram 5] This is a photograph of the test results of experiment 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] The technical solution of the present invention will be described below by specific embodiments with reference to the accompanying drawings. It should be understood that one or more steps mentioned in the present invention do not exclude the existence of other methods and steps before or after the combined steps, or other methods and steps can be inserted between these explicitly mentioned steps. It should be further understood that these examples are only for illustrating the present invention, and do not limit the scope of the present invention. Unless otherwise specified, the number of each method step is only for identifying each method step, and does not limit the order of each method or the implementation scope of the present invention. The change or adjustment of the relative relationship is also considered to be within the scope of the present invention without substantial technical changes.

[0030] The raw materials and equipment used in the examples are not particularly limited in terms of their origin, and may be purchased from the market or prepared by conventional methods well known to those skilled in the art.

[0031] As shown in Figures 1-2, an integrated apparatus for liquid metal-based cleaning and application includes an accumulation table 1 to which a cleaning unit, a wiping unit 3 and an application unit 4 are attached, the accumulation table 1 is attached to a moving mechanism 6, and the integrated apparatus further includes an image sensor 5 for capturing image information.

[0032] The cleaning unit includes a plasma cleaner 21, a first spray head 22 and a second spray head 23, the first spray head 22 is a sodium bicarbonate solution spray head and the second spray head 23 is an anhydrous ethanol spray head, the wiping unit 3 is provided with a wiping device, the coating unit 4 is provided with a coating device, each device is arranged in sequence in a horizontal direction, the working units of each device are exposed to the outside of the accumulation table 1 and perpendicular to the base sample 10, each cleaning device is provided with a containing chamber for containing a cleaning agent, and the coating device is provided with a containing chamber for containing liquid metal.

[0033] The moving mechanism 6 includes an X-direction sliding table 61 and a Z-direction sliding table 62, and the accumulation table 1 is movable left and right and up and down relative to each of the X-direction sliding table 61 and the Z-direction sliding table 62, and further includes a Y-direction sliding table 63, and the accumulation table 1 is movable back and forth relative to the Y-direction sliding table 63.

[0034] The moving mechanism 6 is any device that can realize two-dimensional or three-dimensional spatial movement in the conventional technology. In this embodiment, the accumulation table 1 is fixedly connected to a fixed member, which is slidably mounted on the Z-direction sliding table 62. Both ends of the X-direction sliding table 61 are fixed to the first support frame 71 and the second support frame 72, respectively. Specifically, the first support frame 71 is provided with a first groove 711, and the second support frame is provided with a second groove 721. One end of the X-direction sliding table 61 is mounted on the first groove 711, and the other end is mounted on the second groove 721. The Z-direction sliding table 62 is slidably mounted on the X-direction sliding table 61. The Z-direction sliding table 62 can move the accumulation table 1 and the devices thereon to move left and right along the X-direction sliding table. In order to add the function of moving the accumulation table 1 forward and backward, the Y-direction sliding table 62 is slidably moved on both ends of the X-direction sliding table 61, thereby realizing the accumulation table 1 to move forward and backward along the Y-axis direction.

[0035] A connector 8 is provided at the bottom of each of the first support frame 71 and the second support frame 72 , and the integrated device is fixed to both sides of the production line platform 9 via the connectors 8 .

[0036] In this embodiment, the cleaning devices, wiping devices, coating devices, and image sensor 5 are all connected to a PLC control system, and automation is achieved through PLC control.

[0037] The operating process of the integrated device for liquid metal-based cleaning and coating is as follows.

[0038] In step 1, the image sensor 5 sends the work area image to the computer, the worker notes the work area in the image and checks the required cleaning program, and the computer operates according to the set program.

[0039] JPEG2025501512000003.jpg132147

[0040] Step 3: Check the cleaning effect After the cleaning step is completed, the diffusion area of ​​the organic reagent is used to check whether the cleaning is passed. The larger the diffusion area, the more thoroughly the base is cleaned. Specifically, the computer controls the anhydrous ethanol spray head to drip a drop of anhydrous ethanol onto the workpiece, and controls the image sensor 5 to collect images and upload them to the computer. The computer calculates that the maximum area after the diffusion of the anhydrous ethanol is 6.5 times or more than the area immediately after dripping. If it is less than the set value, it enters the cleaning step again. If it is equal to or greater than the set value, it enters the next step.

[0041] Step 4: Spraying the liquid metal The computer controls the liquid metal application device to apply the liquid metal to the workpiece.

[0042] Comparative experiment: Experiment 1: A nickel-plated copper block simulating that used in a heat sink was taken, washed with a sodium bicarbonate solution, and a drop of absolute ethanol was dropped on it to conduct an experiment. The results are shown in Figure 3. Experiment 2: A nickel-plated copper block simulating that used in a heat sink was taken, washed with absolute ethanol, and a drop of alcohol was dropped on it to perform an experiment. The results are shown in Figure 4. Experiment 3: Take the nickel-plated copper block used in the heat sink, first clean it with plasma cleaner, then with sodium bicarbonate solution, then clean it with ethanol, and add a drop of alcohol to it for verification. The verification results are shown in Figure 5.

[0043] As can be seen by comparing Figures 3 to 5, the liquid metal diffused well on the surface of the nickel-plated copper block cleaned with sodium bicarbonate and ethanol, respectively, indicating that the wettability of the liquid metal on the nickel-plated copper block after cleaning was good.

[0044] Obviously, the problem of non-wetting between the liquid metal and the base can be thoroughly solved by adopting the integrated device of the present invention to repeatedly wash the nickel-plated copper block multiple times.

[0045] Instead of the sodium hydrogen carbonate solution used in the present invention, an aqueous solution of dilute hydrochloric acid, dilute sulfuric acid, dilute nitric acid, hydrobromic acid, hydroiodic acid, phosphoric acid, permanganic acid, carbonic acid, acetic acid, hydrofluoric acid, sodium hydroxide, potassium hydroxide, barium hydroxide, or sodium carbonate may be used.

[0046] Instead of the absolute ethanol used in the present invention, methanol, dipropylene glycol butyl ether, diethylene glycol butyl ether, hydrocarbons, acetone, toluene, ethyl acetate, ethyl ether may be used.

[0047] The method used in the present invention can also be used to plate or adhere liquid metal materials to some materials, such as plastic film materials, metal materials, ceramic materials, etc.

[0048] The cleaning method and the method for inspecting whether cleaning has been passed according to the present invention can also be used in the welding and plating areas of metal materials.

[0049] The foregoing description of specific exemplary embodiments of the present invention is for purposes of explanation and illustration. It is not intended that these descriptions be construed as limiting the invention to the precise forms disclosed, and it is apparent that many modifications and variations are possible in light of the above teachings. The purpose of selecting and describing the exemplary embodiments is to illustrate certain principles of the present invention and their practical applications, so that those skilled in the art can realize and utilize various different exemplary embodiments and various different options and modifications of the present invention. It is intended that the scope of the present invention be limited by the claims and their equivalents.

[0050] In the description of this application, it should be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are orientations or positional relationships according to the drawings, and are intended for convenience or simplification of the description of the present invention, and do not indicate or imply that the referred devices or elements have a specific orientation and are required to be constructed and operated in a specific orientation, and should not be understood as limiting the present invention.

[0051] It should be noted that the terms "first", "second", etc. are merely for explanatory purposes and should not be understood as indicating or suggesting relative importance or implicitly indicating the number of technical features of interest. In the description of the present invention, "plurality" means two or more, unless expressly specified and limited otherwise. [Explanation of symbols]

[0052] 1-accumulation table, 21-plasma cleaning machine, 22-first spray head, 23-second spray head, 3-wiping unit, 4-coating unit, 5-image sensor, 6-moving mechanism, 61-X-direction sliding table, 62-Z-direction sliding table, 63-Y-direction sliding table, 71-first support frame, 711-first groove, 72-second support frame, 721-second groove, 8-connector, 9-production line platform, 10-base sample.

Claims

1. A liquid metal based cleaning method, comprising a base cleaning and an inspection for passing the cleaning, the steps of: The base cleaning may include one or more of a plasma cleaning, an inorganic cleaning agent cleaning, and an organic cleaning agent cleaning, or any combination of the plasma cleaning, the inorganic cleaning agent cleaning, and the organic cleaning agent cleaning; The liquid metal-based cleaning method, characterized in that the inspection of whether the cleaning has been passed is based on the spreading area of ​​the organic reagent on the surface of the liquid metal base, and if the spreading area reaches a predetermined requirement, the cleaning is completed, and if the spreading area does not reach the predetermined requirement, the base cleaning step is repeated, and this repetition continues until the spreading area reaches the predetermined requirement.

2. The inorganic cleaning agent is one selected from the group consisting of a sodium bicarbonate solution, a low-concentration strong acid solution, a high-concentration weak acid solution, a low-concentration strong alkaline solution, and a high-concentration weak alkaline solution. The cleaning method according to claim 1 .

3. The strong acid solution is one or more selected from dilute hydrochloric acid, dilute sulfuric acid, dilute nitric acid, hydrobromic acid, hydroiodic acid, phosphoric acid, and permanganic acid; and / or the weak acid solution is selected from hydrofluoric acid and / or acetic acid; And / or, the strong alkaline solution is one or more selected from sodium oxide, potassium hydroxide, and barium hydroxide; and / or the weak acid solution is selected from sodium bicarbonate and / or sodium carbonate. The cleaning method according to claim 2.

4. The organic reagent is one or more selected from the group consisting of alcohols, hydrocarbons, ethers, esters, and ketones. The cleaning method according to claim 1 .

5. The organic reagent is one or more selected from the group consisting of ethanol, methanol, dipropylene glycol butyl ether, diethylene glycol butyl ether, hydrocarbons, acetone, toluene, ethyl acetate, and ethyl ether. The cleaning method according to claim 1 .

6.

7. 7. An integrated device for liquid metal-based cleaning and application based on the cleaning method according to any one of claims 1 to 6, characterized in that it comprises an accumulation table (1), to which a cleaning unit, a wiping unit (3), an application unit (4) and an image sensor (5) are attached, the accumulation table (1) being attached to a movement mechanism (6).

8. The cleaning unit includes several cleaning devices, the wiping unit (3) is provided with at least one wiping device, and the application unit (4) is provided with at least one application device, preferably the cleaning device includes a plasma cleaner (21), a first spray head (22) and a second spray head (23), the inorganic cleaning agent is placed in the first spray head (22) and the organic cleaning agent is placed in the second spray head (23).

8. The integrated device of claim 7.

9. 9. A method for operating an integrated apparatus according to claim 8, characterized in that the moving mechanism (6) includes an X-direction sliding table (61) and a Z-direction sliding table (62), and the accumulation table (1) is movable left and right and up and down relative to each of the X-direction sliding table (61) and the Z-direction sliding table (62).

10. A method for operating the integrated device of claim 8, comprising the steps of: base cleaning, using one or any combination of the plasma cleaner (21), the first spray bed (22) and the second spray head (23) to clean a liquid metal base surface, and wiping the liquid metal base surface clean with the wiping device after each cleaning is completed; A base inspection is performed by dropping an organic cleaning agent from the second spray head (23) onto the liquid metal base surface, and judging whether the organic cleaning agent is passed or not based on the spreading area of ​​the organic agent on the liquid metal base surface. If the spreading area meets the predetermined requirement, the cleaning is completed; if the spreading area does not meet the predetermined requirement, the base cleaning step is repeated, and the repeat is continued until the spreading area meets the predetermined requirement. A method of applying liquid metal, comprising: a control unit controlling a liquid metal application device to apply liquid metal to the liquid metal base.

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