Hole forming method for low-intermodulation high-frequency module circuit board

Abstract

The invention relates to the technical field of circuit board holing, in particular to a low-intermodulation high-frequency module circuit board holing method, which comprises the following steps of S1, laser drilling, S2, deburring, S3, alkaline oil removal cleaning, S4, coarsening, S5, micro-etching treatment, S6, presoaking, S7, silver deposition and S8, deionized water washing. Alkaline oil removal cleaning in the circuit board is usually composed of a builder and a surfactant, cleaning is conducted again through ionized water after oil removal, it is guaranteed that the surfaces of holes are clean and free of dust, and treatment in the subsequent steps is facilitated; and the hole forming method of the whole circuit board adopts the application of a silver deposition process, so that the electrical performance of the circuit board is improved, the reliability and durability of the circuit board are enhanced, and the interference of transmission signals is reduced, thereby realizing lower low intermodulation, improving the performance of the high-frequency module circuit board, ensuring high-quality completion of plated-through holes in the circuit board, and improving the reliability of the circuit board. And a solid foundation is provided for stable operation of electronic products.

Description

Technical Field

[0001] The invention relates to the technical field of circuit board perforation, and in particular to a method for perforating a circuit board of a low intermodulation high frequency module. Background Art

[0002] Intermodulation interference is generated by nonlinear circuits in the transmission channel. When two or more signals of different frequencies are input into the nonlinear circuit, many harmonics and combined frequency components will be generated due to the action of nonlinear devices. Among them, the combined frequency components close to the required signal frequency ω0 will pass through the receiver smoothly and form interference.

[0003] Therefore, during the use of high-frequency circuit modules, the smaller the intermodulation interference generated by the nonlinear circuit in the transmission channel, the better the transmission performance of the circuit signal. The current circuit board hole-forming method uses copper for the final copper plating, but the electrical performance of the circuit board has not been effectively improved. A low-intermodulation high-frequency module circuit board hole-forming method is needed to solve this problem. Summary of the invention

[0004] The object of the present invention is to provide a method for forming holes in a low intermodulation high frequency module circuit board to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for making holes in a low intermodulation high frequency module circuit board, comprising the following steps:

[0006] S1. Laser drilling: First, the circuit board is drilled according to the size provided by the CAD drawing to form the required via holes. During the drilling process, the circuit board is stably clamped by the clamping assembly to ensure the stability and size accuracy of the drilling process;

[0007] S2. Deburring: Use chemical solution to remove burrs on the edge of the hole to ensure that the smoothness and surface roughness of the hole meet the requirements;

[0008] S3, alkaline degreasing and cleaning: by removing the oil stains, oxides and impurities in the holes on the board surface, the hole wall charge is adjusted to be positive for effective adsorption of palladium particles. After degreasing, cleaning is performed and the copper deposition backlight test is performed to ensure cleanliness;

[0009] S4, coarsening: surface roughness treatment of the hole wall;

[0010] S5, micro-etching treatment: perform slight etching treatment on the circuit board to remove oxides and other impurities on the surface;

[0011] S6, Pre-preg: Pre-preg treatment can enhance the adhesion of subsequent treatments;

[0012] S7, Silver Immersion: The silver immersion reaction is carried out through the replacement reaction between copper and silver ions. On the copper surface treated with micro-etching, it can ensure that a uniform silver immersion layer can be slowly generated at a controlled silver immersion speed;

[0013] S8. Deionized water washing: After the silver precipitation reaction, use deionized water for washing to remove any residual reactants and ensure that the deposited silver layer is pure and free of impurities.

[0014] As a preferred technical solution of the present invention, quality control is required in the entire step. During the entire hole metallization process, strict quality control is required, including chemical analysis of the copper plating solution and the electroplating solution, temperature control, pH value adjustment, etc., to ensure the quality and reliability of the hole metallization.

[0015] As a preferred technical solution of the present invention, the deburring in step S2 utilizes chemical reaction to dissolve the burrs, thereby making the hole wall smooth to ensure the performance and reliability of the circuit board. The deburring can also ensure the smoothness of the hole wall and reduce signal interference.

[0016] As a preferred technical solution of the present invention, the alkaline degreasing cleaning in step S3 uses an alkaline chemical agent, such as an alkaline degreasing agent, which is usually composed of a builder and a surfactant, and is cleaned after degreasing.

[0017] As a preferred technical solution of the present invention, the micro-etching agent in step S5 is a hydrogen peroxide + sulfuric acid system, and the oxides and impurities on the board are removed by the hydrogen peroxide + sulfuric acid system treatment, while the board surface is roughened to enhance the adhesion of chemical copper.

[0018] As a preferred technical solution of the present invention, the pre-immersion in step S6 is mainly to prevent copper and other substances from being brought into the micro-etching tank to contaminate the silver immersion solution.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The present invention is a method for forming holes in a low intermodulation high frequency module circuit board. The alkaline degreasing cleaning agent in the circuit board provided by the present invention is usually composed of a detergent and a surfactant. After degreasing, the holes are cleaned again with ionized water to ensure that the surface of the holes is clean and dust-free, so as to facilitate the processing in subsequent steps. In addition, the method for forming holes in the entire circuit board adopts the silver deposition process, which not only improves the electrical performance of the circuit board, but also enhances its reliability and durability, reduces the interference of the transmission signal, thereby achieving lower low intermodulation, improving the performance of the high frequency module circuit board, ensuring the high quality completion of the metallized holes on the circuit board, and providing a solid foundation for the stable operation of electronic products. DETAILED DESCRIPTION

[0021] The invention is further described below in conjunction with specific implementation methods:

[0022] Example 1

[0023] Embodiment 1 comprises the following steps:

[0024] S1. Laser drilling: First, the circuit board is drilled according to the size provided by the CAD drawing to form the required via holes. During the drilling process, the circuit board is stably clamped by the clamping assembly to ensure the stability and size accuracy of the drilling process;

[0025] S2. Deburring: Use chemical solution to remove burrs on the edge of the hole to ensure that the smoothness and surface roughness of the hole meet the requirements;

[0026] S3, alkaline degreasing and cleaning: by removing the oil stains, oxides and impurities in the holes on the board surface, the hole wall charge is adjusted to be positive for effective adsorption of palladium particles. After degreasing, cleaning is performed and the copper deposition backlight test is performed to ensure cleanliness;

[0027] S4, coarsening: surface roughness treatment of the hole wall;

[0028] In this embodiment, quality control is required in the entire step of the setting. Strict quality control is required in the entire hole metallization process, including chemical analysis of the copper plating solution and the electroplating solution, temperature control, pH adjustment, etc., to ensure the quality and reliability of the hole metallization. The deburring in step S2 utilizes chemical reactions to dissolve burrs, thereby making the hole wall smooth to ensure the performance and reliability of the circuit board. Deburring can also ensure the smoothness of the hole wall and reduce signal interference. Alkaline chemical preparations such as alkaline degreasing agents are used in alkaline degreasing cleaning in step S3. This preparation is usually composed of a detergent and a surfactant, and is cleaned after degreasing.

[0029] Example 2

[0030] Embodiment 2, this embodiment further illustrates embodiment 1, and includes the following steps: S5, micro-etching treatment: performing a slight etching treatment on the circuit board to remove oxides and other impurities on the surface;

[0031] S6, Pre-preg: Pre-preg treatment can enhance the adhesion of subsequent treatments;

[0032] S7, Silver Immersion: The silver immersion reaction is carried out through the replacement reaction between copper and silver ions. On the copper surface treated with micro-etching, it can ensure that a uniform silver immersion layer can be slowly generated at a controlled silver immersion speed;

[0033] S8, deionized water washing: after the silver precipitation reaction, use deionized water for washing to remove any residual reactants and ensure that the deposited silver layer is pure and free of impurities;

[0034] In this embodiment, the micro-etching agent in step S5 is a hydrogen peroxide + sulfuric acid system. The oxides and impurities on the board are removed by the hydrogen peroxide + sulfuric acid system treatment, and the board surface is roughened to enhance the adhesion of chemical copper. The pre-immersion in step S6 is mainly to prevent copper and other substances from being brought into the micro-etching tank to contaminate the silver immersion solution.

[0035] In the description of the present invention, it should be noted that the terms "top", "bottom", "one side", "the other side", "front", "back", "middle part", "inside", "top", "bottom" and the like indicating the orientation or positional relationship are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention; the terms "first", "second", and "third" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance; in addition, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for forming a hole in a low intermodulation high frequency module circuit board, characterized in that: The following steps are involved: S1. Laser drilling: First, the circuit board is drilled according to the size provided by the CAD drawing to form the required via holes. During the drilling process, the circuit board is stably clamped by the clamping assembly to ensure the stability and size accuracy of the drilling process; S2. Deburring: Use chemical solution to remove burrs on the edge of the hole to ensure that the smoothness and surface roughness of the hole meet the requirements; S3, alkaline degreasing and cleaning: by removing the oil stains, oxides and impurities in the holes on the board surface, the hole wall charge is adjusted to be positive for effective adsorption of palladium particles. After degreasing, cleaning is performed and the copper deposition backlight test is performed to ensure cleanliness; S4, coarsening: surface roughness treatment of the hole wall; S5, micro-etching treatment: perform slight etching treatment on the circuit board to remove oxides and other impurities on the surface; S6, Pre-preg: Pre-preg treatment can enhance the adhesion of subsequent treatments; S7, Silver Immersion: The silver immersion reaction is carried out through the replacement reaction between copper and silver ions. On the copper surface treated with micro-etching, it can ensure that a uniform silver immersion layer can be slowly generated at a controlled silver immersion speed; S8. Deionized water washing: After the silver precipitation reaction, use deionized water for washing to remove any residual reactants and ensure that the deposited silver layer is pure and free of impurities.

2. The method for forming a hole in a low intermodulation high frequency module circuit board according to claim 1, characterized in that: Quality control is required throughout the entire step. Strict quality control is required throughout the entire hole metallization process, including chemical analysis of the copper plating solution and the electroplating solution, temperature control, pH adjustment, etc., to ensure the quality and reliability of the hole metallization.

3. The method for forming a hole in a low intermodulation high frequency module circuit board according to claim 1, characterized in that: The deburring in step S2 utilizes chemical reactions to dissolve burrs, thereby making the hole wall smooth to ensure the performance and reliability of the circuit board. Deburring can also ensure the smoothness of the hole wall and reduce signal interference.

4. The method for forming holes in a low intermodulation high frequency module circuit board according to claim 1, characterized in that: The alkaline degreasing cleaning in step S3 uses an alkaline chemical agent, such as an alkaline degreasing agent, which is usually composed of a builder and a surfactant, and is used for cleaning after degreasing.

5. The method for forming holes in a low intermodulation high frequency module circuit board according to claim 1, characterized in that: In step S5, the micro-etching agent is a hydrogen peroxide + sulfuric acid system, and the oxides and impurities on the board are removed by the hydrogen peroxide + sulfuric acid system treatment, while the board surface is roughened to enhance the adhesion of chemical copper.

6. The method for forming holes in a low intermodulation high frequency module circuit board according to claim 1, characterized in that: The pre-immersion in step S6 is mainly to prevent copper and other substances from being brought into the micro-etching tank to contaminate the silver immersion solution.