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 cleaning and application apparatus," 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 to traditional silicone greases, liquid metals have a higher surface tension, making them difficult to spread between the chip and heat sink. Poor application can significantly impact the chip's heat dissipation performance and lead to product defects. Currently, there are two main approaches to this problem. One is to modify the liquid metal, increasing its viscosity at the expense of some of its thermal conductivity, thereby reducing the difficulty of applying it to the base. The other approach involves applying the liquid metal dozens of times. This approach, similar in principle to the modification process, also sacrifices some of its thermal conductivity and shortens the liquid metal's service life. Since neither of these approaches effectively solves the wetting issue between the liquid metal and the base, a solution is needed that can effectively address the wetting issue between the liquid metal and the base without compromising the liquid metal's performance, while ensuring ease of application and facilitating mass production.

[0004] Because liquid metal is an emerging industry, there is currently no integrated device on the market that can be used for both liquid metal base cleaning and liquid metal application. The conventional solution is to use multiple devices with a single function in combination, which is disadvantageous for the industry to adopt this technology.

[0005] The information disclosed in this background is intended only to enhance understanding of the general context of the present invention and should not be taken as an admission or in any way suggestion 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] To solve the technical problems of the prior art, where application of liquid metal is difficult and sacrifices part of the thermal conductivity 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] This invention is realized mainly by cleaning chips and heat sinks. Although chips and heat sinks appear clean to the human eye, they actually have a thin layer of dirt on their surfaces, which mainly consists of organic and inorganic substances. If these two types of substances are removed by cleaning, the liquid metal will theoretically have good wetting properties for the 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 plasma cleaning, and / or cleaning with an inorganic cleaning agent, and / or cleaning with an organic reagent, or any combination of the plasma cleaning, cleaning with an inorganic cleaning agent, and cleaning with an organic reagent; The inspection of whether the cleaning is acceptable is determined based on the spreading area of ​​the organic reagent on the liquid metal base surface, and 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 this repetition continues until the spreading area meets the predetermined requirement. Preferably, the predetermined requirement is that the maximum spreading area of ​​the organic reagent on the base surface after cleaning is at least 6.5 times 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] In some embodiments, the base wash comprises: Plasma cleaning method JPEG2024055486000007.jpg56, and / or a method of cleaning with an inorganic cleaning agent. JPEG2024055486000008.jpg55, and / or washing with an organic reagent. JPEG2024055486000009.jpg55, and / or a combination cleaning method, where first a plasma cleaning is performed and then a cleaning with an inorganic cleaning agent is performed. JPEG2024055486000010.jpg56, and / or a combination cleaning method, where first a plasma cleaning is performed and then a cleaning with an organic reagent is performed. JPEG2024055486000011.jpg55, and / or a combination cleaning method, first cleaning with an inorganic cleaning agent and then plasma cleaning. JPEG2024055486000012.jpg56, and / or a combination cleaning method, first cleaning with an inorganic cleaning agent and then cleaning with an organic reagent. JPEG2024055486000013.jpg56, and / or a combination cleaning method, first cleaning with an organic reagent and then plasma cleaning. JPEG2024055486000014.jpg55, and / or a combination cleaning method, first cleaning with an organic reagent and then cleaning with an inorganic cleaning agent. JPEG2024055486000015.jpg56, and / or a combination cleaning method, first a plasma cleaning, then a cleaning with an inorganic cleaning agent, and then a cleaning with an organic reagent. JPEG2024055486000016.jpg55, and / or a combination cleaning method, first a plasma cleaning, then a cleaning with an organic reagent, and then a cleaning with an inorganic cleaning agent. JPEG2024055486000017.jpg55, and / or a combination cleaning method, first cleaning with an inorganic cleaning agent, then plasma cleaning, and then cleaning with an organic reagent. JPEG2024055486000018.jpg55, and / or a combination cleaning method, first cleaning with an inorganic cleaning agent, then cleaning with an organic reagent, and then plasma cleaning. JPEG2024055486000019.jpg56, and / or a combination cleaning method, first cleaning with an organic reagent, then plasma cleaning, and then cleaning with an inorganic cleaning agent. JPEG2024055486000020.jpg55, and / or a combination cleaning method, first cleaning with an organic reagent, then cleaning with an inorganic cleaning agent, and then plasma cleaning. Contains JPEG2024055486000021.jpg56.

[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 detergent is sodium bicarbonate solution and the organic reagent is absolute ethanol.

[0017] According to a second aspect of the present invention, there is provided an integrated device for cleaning and applying a liquid metal base, which includes an accumulation table to which a cleaning unit, a wiping unit, an application unit, and an image sensor are attached, and the accumulation table is attached to a movement mechanism. The cleaning, wiping, and application functions are integrated into a single device, and image information is captured by an image sensor and sent to a control system to realize the movement and positioning of the device. Subsequently, the base is repeatedly cleaned and wiped according to a program, completely removing oil stains and other contaminants from the surface of the base. After the base is cleaned, application can be performed directly, eliminating the intermediate transfer process and avoiding secondary contamination.

[0018] In some embodiments, the cleaning unit includes several 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: 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 wiping device after each cleaning; 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 spread area of ​​the organic agent on the liquid metal base surface; if the spread area meets the predetermined requirement, the cleaning is completed; if the spread area does not meet the predetermined requirement, the base cleaning step is repeated; and this is repeated until the spread area meets the predetermined requirement; The method includes applying the liquid metal, and the computer controls a liquid metal application device to apply the 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 externally mounted design allows for retrofitting to most conventional production lines.

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

[0022] In some embodiments, the cleaning device 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 absolute 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 collection table is movable back and forth relative to the Y-direction sliding table. By installing the X-direction sliding table, the Z-direction sliding table, and the Y-direction sliding table, the movement of the collection table in three-dimensional space is realized.

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

[0027] Compared with the prior art, the technical advantages achieved by the present invention are as follows: (1) Compared with conventional solutions, the method and apparatus of the present invention thoroughly cleans the base surfaces of the chip and heat sink, fundamentally solving the problem of liquid metal not wetting the base. Unmodified liquid metal solution can be quickly and uniformly applied to the base surfaces of the chip and heat sink, preventing loss of thermal conductivity of the liquid metal and ensuring good contact between the liquid metal and the base of the chip and heat sink, eliminating obstructions caused by dirty films and improving heat dissipation. The good contact also alleviates the problem of liquid metal adhesion between the chip and heat sink and leakage due to high surface tension. Failure to clean in accordance with this apparatus and method, or cleaning poorly, can lead to liquid metal leakage 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, which meets the automation needs of the liquid metal industry. The external installation design makes it suitable for retrofitting to most existing production lines, allowing for the rapid upgrade of existing production lines. The design of multiple cleaning methods also makes it easy for manufacturers to choose according to their actual situations. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is a structural schematic diagram of the present invention; [Figure 2] 3 is a schematic diagram of the mechanisms of a first support frame and a second support frame. FIG. [Figure 3] This is a photograph of the test results of Experiment 1. [Figure 4] This is a photograph of the test results of Experiment 2. [Figure 5] This is a photograph of the test results of Experiment 3. DETAILED DESCRIPTION OF THE INVENTION

[0029] The technical solutions of the present invention will be described below through 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 that other methods and steps can be inserted between these explicitly mentioned steps. It should be further understood that these examples are only for the purpose of explaining the present invention and do not limit the scope of the present invention. Unless otherwise specified, the numbers of each method step are only for identifying each method step and do not limit the order of each method step or the scope of the present invention. Changes or adjustments to the relative relationships are also considered to be within the scope of the present invention without any substantial changes to the technical content.

[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 and 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, and 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, and the coating unit 4 is provided with a coating device. Each device is arranged horizontally in sequence, and the operating 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 storage chamber for storing a cleaning agent, and the coating device is provided with a storage chamber for storing 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 can move 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 can move back and forth relative to the Y-direction sliding table 63.

[0034] The moving mechanism 6 is any device capable of two-dimensional or three-dimensional spatial movement, as in conventional Wei technology. In this embodiment, the accumulation table 1 is fixedly connected to a fixed member, which is slidably attached to the Z-direction sliding table 62. The 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 attached to the first groove 711, and the other end is attached to the second groove 721. The Z-direction sliding table 62 is slidably attached to the X-direction sliding table 61, which can move the accumulation table 1 and the devices mounted thereon left and right along the X-direction sliding table. To add the function of moving the accumulation table 1 forward and backward, the Y-direction sliding tables 62 are slidably attached to both ends of the X-direction sliding table 61, allowing the accumulation table 1 to move forward and backward along the Y-axis.

[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 device, wiping device, coating device, 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 application 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] JPEG2024055486000022.jpg253170

[0040] Step 3: Check the cleaning effect After the cleaning step is completed, the area of ​​diffusion of the organic reagent is checked to see if the cleaning is successful. The larger the diffusion area, the better 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 anhydrous ethanol has been diffused is 6.5 times or more than the area immediately after dripping. If it is less than the set value, the cleaning step is resumed. If it is greater than the set value, the next step is started.

[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 sodium bicarbonate solution, and a drop of absolute ethanol was added for verification. The verification results are shown in Figure 3. Experiment 2: A nickel-plated copper block simulating that used in the heat sink was taken, washed with absolute ethanol, and a drop of alcohol was dropped on it to conduct the test. The test results are shown in Figure 4. Experiment 3: The nickel-plated copper block used in the heat sink was taken and first cleaned with plasma cleaner and sodium bicarbonate solution, then cleaned with ethanol, and a drop of alcohol was added for testing. The test results are shown in Figure 5.

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

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

[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, and ethyl ether may be used.

[0047] The method used in the present invention is applicable to plastic film materials, metal materials, ceramic materials, etc. MaterialsIt can also be used to plate or bond liquid metal materials.

[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 descriptions of specific exemplary embodiments of the present invention are for purposes of explanation and illustration. They are not intended to limit the invention to the precise forms disclosed, and obviously, many modifications and variations are possible in light of the above teachings. The purpose of selecting and describing exemplary examples is to explain 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 of the present invention and various different choices and modifications. 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 orientations or positional relationships indicated by terms such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "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 the convenience and simplification of the description of the present invention, and do not indicate or imply that the referred-to devices or elements need to have a particular orientation or be constructed and operated in a particular 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 covered. 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 - application unit, 5 - image sensor, 6 - movement 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. 1. A liquid metal-based cleaning method, comprising a base cleaning and an inspection for passing the cleaning, the steps of: The base cleaning includes plasma cleaning, cleaning with inorganic cleaning agents, and cleaning with organic reagents; The liquid metal-based cleaning method is characterized in that the inspection of whether the cleaning has passed is based on the spreading area of ​​the organic reagent on the surface of the liquid metal base, and if the spreading area meets a predetermined requirement, the cleaning is completed, and if the spreading area does not meet the predetermined requirement, the base cleaning step is repeated, and this repetition continues until the spreading area meets the predetermined requirement, and the predetermined requirement is that the maximum area after spreading of the organic reagent on the base surface after cleaning is 6.5 times or more of the area when it was dropped before cleaning.

2. The inorganic detergent is one selected from a strong acid solution, a weak acid solution, a strong alkaline solution, and a weak alkaline solution, 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 alkaline solution is selected from sodium bicarbonate and / or sodium carbonate. The cleaning method according to claim 1 .

3. 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 .

4. 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 .

5. The base cleaning method includes: Perform a combination clean, first a plasma clean, then a clean with an inorganic cleaner, and then a clean with an organic reagent. 、 and / or performing a combination clean, first a plasma clean, then a clean with an organic reagent, and then a clean with an inorganic cleaner. 、 and / or performing a combination clean, first with an inorganic cleaner, then with a plasma clean, and then with an organic reagent. 、 and / or performing a combination clean, first with an inorganic cleaner, then with an organic reagent, and then with a plasma clean. 、 and / or performing a combination clean, first cleaning with an organic reagent, then a plasma clean, and then cleaning with an inorganic cleaner. 、 and / or performing a combination clean, first with an organic reagent, then with an inorganic cleaner, and then with a plasma clean. characterized in that it comprises The cleaning method according to claim 1 .

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

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

7. The integrated device of claim 6.

8. 8. A method for operating an integrated device according to claim 7, wherein the movement 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).

9. 8. A method for operating the integrated device of claim 7, comprising: a base cleaning step in which the liquid metal base surface is cleaned using one or any combination of the plasma cleaner (21), the first spray bed (22), and the second spray head (23), and the liquid metal base surface is wiped clean by the wiping device after each cleaning step is completed; a base inspection, in which the organic cleaning agent in the second spray head (23) is dropped onto the liquid metal base surface, and whether it passes is judged based on the spreading area of ​​the organic agent on the liquid metal base surface; if the spreading area reaches a predetermined requirement, the cleaning is completed; if the spreading area does not reach a predetermined requirement, the base cleaning step is repeated; and this is repeated until the spreading area reaches a predetermined requirement; applying liquid metal, the method comprising: a control unit controlling a liquid metal application device to apply liquid metal to the liquid metal base.

Images