Bonding process based on plasma treatment

Abstract

The invention relates to the field of communication equipment manufacturing, and discloses a bonding process based on plasma treatment, which comprises the following steps of: carrying out surface silver plating treatment on a metal cavity of a carrier part, obtaining a bonding position coordinate in the metal cavity, and according to the bonding position coordinate, carrying out plasma treatment on the metal cavity. The method comprises the following steps of: performing flame jet treatment on a bonding position in a metal cavity by utilizing plasma flame to realize rapid cleaning of a metal surface and activation of an oxide layer, improving the firmness of a non-metal element bonded to the metal surface, and then coating glue for bonding to the bonding position, so as to obtain a non-metal element bonded to the metal surface; according to the method, the carrier component and the functional component are bonded at the bonding position, then the functional component is placed at the bonding position and then pressed, the target integrated component is formed after the functional component and the carrier component are bonded, baking treatment is conducted after bonding of the target integrated component is completed, it can be guaranteed that the performance of glue reaches the best, cost reduction and efficiency improvement are achieved, and the competitiveness of products is improved.

Description

Technical Field

[0001] This invention relates to the field of communication equipment manufacturing, and more specifically to a bonding process based on plasma treatment. Background Technology

[0002] In recent years, the rapid development of microwave communication technology has driven the rapid upgrading of the high-frequency microwave passive device industry. The widespread application of non-metallic material components facilitates the integration and reconfiguration of single-component functions, significantly improving the overall system performance; for example, TE-mode dielectric resonators in the 5-11 GHz range have been integrated into microwave filters, but this also places higher demands on manufacturers' processing and bonding techniques.

[0003] Currently, the main methods for treating the protective layer of such bonded areas are mechanical grinding or secondary NC machining after surface treatment. Adding these processes to the conventional production flow not only requires a significant investment of manpower and resources but may also lead to problems such as processing failures, incomplete surface cleaning, and residue, which does not meet the requirements of lean manufacturing. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a bonding process based on plasma treatment. By spraying the bonding site with plasma flame, the metal surface can be quickly cleaned and the oxide layer activated, thereby improving the adhesion of non-metallic components to the metal surface and solving the bonding problem in the communication filter industry.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A plasma-based bonding process includes the following steps: S1. The metal cavity of the carrier component is subjected to silver plating treatment to form a surface silver layer on the surface of the metal cavity. S2. Obtain the bonding position coordinates within the metal cavity; S3. Based on the bonding position coordinates, use a plasma flame to perform flame spraying treatment on the bonding position inside the metal cavity. S4. The metal cavity is inspected at the bonding location after being treated with flame jetting. S5. Place the metal cavity horizontally, apply adhesive to the bonding position, place the functional component into the bonding position and press it to bond the functional component to the carrier component to form the target integrated assembly. S6. After the target integrated component is bonded, it is then baked.

[0006] Optionally, in step S3, when performing flame jetting on the bonding positions, the plasma flame remains at each bonding position for 3-5 seconds.

[0007] Optionally, after the metal cavity in step S1 is silver-plated, it is baked at 150-250°C for 1.5-2.5 hours, and the surface silver layer is checked for defects after baking.

[0008] Optionally, in step S6, when the target integrated component is baked, the baking temperature is 100-150℃ and the baking time is 1.5-2.5 hours.

[0009] Optionally, after the target integrated component undergoes baking treatment, it is subjected to thrust testing to determine whether it is qualified.

[0010] Optionally, the adhesive is used to bond the functional component and the carrier component, and the adhesive is a thermosetting epoxy polymer adhesive.

[0011] Optionally, multiple bonding positions are provided and adopt a groove structure, and the bonding positions are located inside the metal cavity.

[0012] Optionally, the carrier component is a microwave device with input and output ports, the functional component is a TE-mode dielectric resonator, the target integrated component is a microwave dielectric filter, and multiple TE-mode dielectric resonators are installed in the metal cavity of the microwave device to form a microwave dielectric filter.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) In this invention, silver plating of the metal cavity can increase the conductivity of the metal conductor and reduce the signal loss of electromagnetic signals passing through the filter. Plasma flame spraying treatment of the bonding position can achieve rapid cleaning of the metal surface and activation of the oxide layer, and improve the adhesion of non-metallic components to the metal surface, such as the adhesion between functional components and carrier components. Compared with the existing protective layer treatment methods, plasma flame spraying treatment has low cost and good effect, and can achieve cost reduction and efficiency improvement, and improve the competitiveness of the product. (2) In this invention, after the functional component is placed in the bonding position of the carrier component, the effectiveness of the adhesive bonding can be ensured by pressing. Then, the baking process can ensure that the performance of the adhesive reaches the best. (3) In this invention, the surface of the bonding position is inspected before bonding to ensure the bonding effect of the functional components on the carrier components and improve product quality; (4) In this invention, the bonding position adopts a groove structure, which not only facilitates the application of adhesive, but also enables the functional components to be positioned on the carrier components, ensuring the positional accuracy of the bonding process. Attached Figure Description

[0014] Figure 1This is a schematic flowchart of the bonding process based on plasma treatment in an embodiment of the present invention; Detailed Implementation

[0015] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. These drawings are simplified schematic diagrams, which are only used to illustrate the basic structure of the invention and therefore only show the components relevant to the invention.

[0016] A microwave dielectric filter comprises a microwave device and multiple TE-mode dielectric resonators. The microwave device's metal cavity has input and output ports, typically using an aluminum alloy as the shielding substrate with a silver-plated surface finish. A certain number of TE-mode dielectric resonators are mounted within the metal cavity, together forming a frequency-selective microwave dielectric filter. Therefore, the microwave device is equivalent to the carrier component, and the TE-mode dielectric resonators are equivalent to the functional components. By mounting the functional components onto the carrier component, the target integrated assembly, i.e., the microwave dielectric filter, can be obtained.

[0017] As the operating frequency increases, the overall size of the electromagnetic resonator can be reduced several times. However, the diameter of the alumina support base is only 3mm. Since the functional components cannot be installed on the metal cavity using threaded fastening, an adhesive bonding process is required to connect these functional components to the carrier components, thereby obtaining the target integrated assembly.

[0018] Among them, the TE mode dielectric resonator is an electromagnetic resonant energy storage element with a high Q value. It is made of specific ceramic materials and has a cylindrical or ring-shaped shape. Its size decreases as the frequency increases. When the operating frequency exceeds 5GHz, the TE mode dielectric resonator is too small to be fixed with screws and can only be glued.

[0019] like Figure 1 As shown, this invention proposes a bonding process based on plasma treatment, including the following steps: surface treatment of the metal cavity, obtaining the bonding position coordinates, performing plasma flame spraying treatment, surface inspection before bonding, bonding operation to obtain the finished product, baking the bonded finished product, and detecting the bonding quality of the finished product.

[0020] Surface treatment of the metal cavity: The metal cavity of the carrier component is silver-plated to form a surface silver layer. After the surface silver plating, the metal cavity is baked at 150-250℃ for 1.5-2.5 hours, and the surface silver layer is checked for any defects after baking.

[0021] Silver plating of metal cavities can increase the conductivity of metal conductors and reduce the signal loss of electromagnetic signals passing through filters. Silver plating of aluminum alloys is a surface treatment technology that deposits a silver layer on the metal surface through a chemical process, so the adhesion of the silver layer is reliable in the long term.

[0022] After the cavity of the metal filter has undergone surface silver plating, it needs to be baked and cured to optimize the performance of the silver layer and improve its reliability. This process removes residual impurities from the plating, improves surface cleanliness, and prevents defects such as pinholes, bubbles, and discoloration caused by residual impurities, ensuring a clean silver layer surface. It also enhances the adhesion between the silver layer and the substrate, preventing peeling and flaking, thus avoiding silver layer peeling and flaking during subsequent processing and assembly, and preventing insufficient adhesion from affecting the filter's signal transmission and lifespan. Furthermore, it releases internal stress in the plating, improving structural stability and preventing cracking due to stress concentration when the ambient temperature changes. It also improves the wear resistance and deformation resistance of the silver layer, ensuring the dimensional accuracy and surface integrity of the metal cavity. Finally, it optimizes the conductivity and oxidation resistance of the silver layer. For microwave devices, increased conductivity reduces signal transmission loss, and enhanced oxidation resistance extends the cavity's lifespan, preventing the silver layer from blackening and affecting performance.

[0023] For example, after the metal cavity is silver-plated, it is baked at 200°C for 2 hours, and the surface silver layer, especially inside the cavity, is inspected for defects such as blistering and peeling to ensure that there are no defects such as blistering or peeling inside the metal cavity during bonding. Furthermore, after baking the silver layer at 200°C, an impact test is performed to assess the bonding strength, and the quality of the silver layer after the impact is used as the inspection standard.

[0024] Obtain the bonding position coordinates: Obtain the bonding position coordinates inside the metal cavity. Since multiple TE mode dielectric resonators are installed inside the metal cavity of the microwave device, multiple bonding positions are also set and located inside the metal cavity. Moreover, the bonding positions adopt a groove structure, which not only facilitates the subsequent application of adhesive, but also enables the functional components to be positioned on the carrier components, ensuring the positional accuracy of the bonding process.

[0025] Here, we select the existing 800W low-temperature atmospheric plasma semi-automatic equipment, equipped with a desktop work platform and a handheld control interface. By inputting product drawings and editing the work program, the coordinates of the adhesive position can be clearly defined.

[0026] Plasma flame blasting treatment: Based on the coordinates of the bonding positions, a plasma flame is used to blast the bonding positions within the metal cavity. During flame blasting, the plasma flame remains at each bonding position for 3-5 seconds, resulting in a burnt yellow silver layer. The purpose of plasma flame blasting is to alter the activity of the protective film on the silver-plated surface of the metal cavity filter, causing a chemical change in its molecular structure. It also removes surface grease and microscopic contaminants, primarily utilizing plasma to clean, activate, and modify the object's surface.

[0027] The microwave device (metal cavity) is placed on the work platform, and the automatic program of the equipment is started. The excited plasma flame is sprayed onto several grooves in the cavity, with a dwell time of 3-5 seconds at each point, until the plasma flame spraying treatment of all bonding positions is completed. A plasma generator is a device for artificially obtaining plasma, typically consisting of five parts: a vacuum cavity, a vacuum pump system, a radio frequency power supply, a gas supply system, and a control system. The power supply parameters selected in this invention are: gas pressure 0.36 MPa, output frequency: 23 kHz. It does not belong to traditional wet chemical cleaning or mechanical polishing, but rather a dry integrated treatment process. The principle is to use electrical energy to excite process gases (such as oxygen, argon, helium, nitrogen-hydrogen mixtures, etc.) into a plasma state within a vacuum cavity.

[0028] Surface inspection before bonding: After the metal cavity is treated with flame spraying, the surface of its bonding position is inspected. That is, the surface of the groove is inspected before bonding to ensure that the inner surface is clean and to avoid residual impurities. This can ensure the bonding effect of functional components on carrier components and improve product quality.

[0029] The bonding process yields the finished product: The metal cavity is placed horizontally. Adhesive is applied to the bonding area, and the functional component is placed into the bonding area and pressed down to bond the functional component to the carrier component, forming the target integrated assembly. Alternatively, after placing the cavity horizontally, a certain amount of adhesive is applied to the cavity's groove. Wearing gloves, the TE mode dielectric resonator is placed into the groove for bonding, and pressure is applied by hand to ensure effective bonding.

[0030] Bake the bonded finished product: After the target integrated components are bonded, they are baked. When baking the target integrated components, the baking temperature is 100-150℃ and the baking time is 1.5-2.5 hours. After the functional parts are placed in the bonding position of the carrier parts, the effectiveness of the adhesive bonding can be ensured by pressing. The subsequent baking process can ensure that the performance of the adhesive reaches the best.

[0031] For example, the target integrated components to be bonded are baked at 120°C for 2 hours to ensure the adhesive performance reaches its optimal level. The adhesive is used to bond functional components and carrier components. Here, a thermosetting epoxy polymer adhesive, such as EP1330LV single-component, is used; it requires no mixing and can be used directly. The typical temperature range is 100-150°C.

[0032] Testing the bonding quality of finished products: After the target integrated components are baked, they are subjected to a thrust test to determine whether they are qualified. That is, a thrust test is performed on the bonded TE mode dielectric resonator. A thrust of 10 Nm is manually applied to the thrust gauge. If the TE mode dielectric resonator does not detach from the microwave device, it is a qualified product.

[0033] Once the finished product passes inspection, the metal cavity of the microwave device can be transferred to the next process.

[0034] In summary, the plasma-based bonding process proposed in this invention can achieve rapid cleaning and oxide layer activation of metal surfaces through a high-power plasma machine, thereby improving the adhesion of non-metallic components to metal surfaces. This solves a bonding problem that is quite challenging for process engineers in related industries. It represents a high-level optimization of bonding processes in the communication microwave passive device industry, achieving cost reduction and efficiency improvement, which is of great economic value and can enhance product competitiveness.

[0035] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many improvements and modifications under the guidance of the present invention without departing from the spirit and scope of the claims. These improvements and modifications should also be considered within the scope of protection of the present invention.

[0036] In the description of this invention, it should be understood that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0037] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0038] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

Claims

1. A bonding process based on plasma treatment, characterized in that, Includes the following steps: S1. The metal cavity of the carrier component is subjected to silver plating treatment to form a surface silver layer on the surface of the metal cavity. S2. Obtain the bonding position coordinates within the metal cavity; S3. Based on the bonding position coordinates, use a plasma flame to perform flame spraying treatment on the bonding position inside the metal cavity. S4. The metal cavity is inspected at the bonding location after being treated with flame jetting. S5. Place the metal cavity horizontally, apply adhesive to the bonding position, place the functional component into the bonding position and press it to bond the functional component to the carrier component to form the target integrated assembly. S6. After the target integrated component is bonded, it is then baked.

2. The bonding process based on plasma treatment according to claim 1, characterized in that, In step S3, when performing flame jetting on the bonding positions, the plasma flame remains at each bonding position for 3-5 seconds.

3. The plasma-based bonding process according to claim 2, characterized in that, In step S1, after the metal cavity is silver-plated, it is baked at 150-250°C for 1.5-2.5 hours, and the surface silver layer is checked for defects after baking.

4. The plasma-based bonding process according to claim 3, characterized in that, In step S6, when the target integrated component is baked, the baking temperature is 100-150℃ and the baking time is 1.5-2.5 hours.

5. The plasma-based bonding process according to claim 4, characterized in that, After the target integrated component undergoes baking treatment, it is subjected to thrust testing to determine whether it is qualified.

6. The plasma-based bonding process according to claim 5, characterized in that, The adhesive is used to bond the functional component and the carrier component, and the adhesive is a thermosetting epoxy polymer adhesive.

7. The plasma-based bonding process according to claim 1, characterized in that, The bonding positions are provided in multiple locations and adopt a groove structure, and the bonding positions are located inside the metal cavity.

8. The plasma-based bonding process according to any one of claims 1-7, characterized in that, The carrier component is a microwave device with input and output ports, the functional component is a TE-mode dielectric resonator, the target integrated component is a microwave dielectric filter, and multiple TE-mode dielectric resonators are installed in the metal cavity of the microwave device to form a microwave dielectric filter.

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