Method for measuring copper deposition binding force

Abstract

The invention discloses a method for measuring copper deposition binding force, which comprises the following steps of: S1, selecting a basic copper-clad plate, and reserving a base material of the copper-clad plate by etching a copper foil on the surface of the copper-clad plate; s2, copper deposition is carried out on the base material, the copper deposition backlight is made to be larger than or equal to 9 levels through vertical copper deposition or horizontal copper deposition, electroplating is carried out after copper deposition, and the thickness of an electroplated copper layer is 30-35 microns; s3, manufacturing a circuit pattern on the base material after the step S2; s4, using an instrument for measuring the peel strength, picking up the copper sheet at one end of the circuit pattern, fixing the copper sheet on a clamp of the instrument for measuring the peel strength, returning the tensile force of the instrument for measuring the peel strength to zero, starting the instrument for measuring the peel strength, slowly rising the clamp until the circuit pattern is completely peeled from the base material, recording the tensile force value required in the process, and recording the tensile force value in the process. Calculating the peel strength, wherein the peel strength = tensile force (N) / line width (mm); and the numerical value of the copper deposition bonding force is accurately measured through the peel strength test, so that the quantification of the copper deposition bonding force is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of electronic manufacturing, and in particular relates to a method for measuring the bonding strength of copper deposition. Background Art

[0002] With the rapid development of electronic technology, multilayer printed circuit boards (PCBs) have been widely used in various electronic devices due to their high density, high performance and multifunctionality. In the manufacturing process of multilayer PCBs, it is a crucial step to achieve conductive connections between different layers through drilling, copper plating, electroplating and other processes. Among them, the copper plating process is to deposit conductive metal copper on the surface of a non-conductive substrate to form a thin copper film so that the subsequent electroplating process can proceed smoothly. The bonding strength of the copper plating layer directly affects the reliability and service life of the final product. Therefore, the detection of the bonding strength of the copper plating is particularly important.

[0003] The traditional method of detecting the bonding strength of copper plating is mainly to judge whether the copper in the hole is separated from the hole wall by observing through slices. Specifically, the technician will take a small sample from the PCB board after copper plating, and use a microscope or scanning electron microscope (SEM) to observe the interface between the copper in the hole and the hole wall to determine whether there is a separation phenomenon. Although this method can reflect the quality of the copper plating bonding strength to a certain extent, it has obvious limitations. First, slice observation can only provide qualitative results, that is, qualified or unqualified, and cannot quantify the specific value of the copper plating bonding strength. Secondly, this method relies on the experience and skills of the operator and is easily affected by subjective factors, resulting in inconsistency and non-repeatability of the results. In addition, slice observation requires the destruction of the sample, and it is impossible to test the same sample multiple times, which may cause waste in actual production.

[0004] In recent years, with the continuous improvement of PCB product quality requirements, the traditional copper bonding strength detection method can no longer meet the needs of modern production. Especially in the fields of high-end electronic products, military, aerospace, etc., the reliability and stability of PCBs are extremely strict, and any slight defect may cause the failure of the entire system. Therefore, it is urgent to develop a method that can quantitatively measure the bonding strength of copper. Summary of the invention

[0005] In order to overcome the shortcomings of the prior art, the present invention provides a method for measuring the bonding strength of copper deposits. The square This method aims to solve the problem that the existing copper bonding strength detection method can only make qualitative judgments but cannot be quantified. The paper aims to provide a simple, efficient and reliable method for quantitatively measuring the bonding strength of copper plating to improve the quality and reliability of PCB products.

[0006] In order to solve the above problems, the technical solution adopted by the present invention is as follows: A method for measuring the bonding strength of copper deposition, characterized in that it comprises the following steps:

[0007] S1: Select a basic copper-clad laminate, and retain the base material of the copper-clad laminate by etching the copper foil on the surface of the copper-clad laminate.

[0008] S2: copper is deposited on the substrate by using vertical copper deposition or horizontal copper deposition to make the copper deposition backlight ≥ level 9, and then electroplating is performed after copper deposition, and the thickness of the electroplated copper layer is 30 to 35 μm.

[0009] S3: making a circuit pattern on the substrate after the above step S2;

[0010] S4: Use an instrument for measuring peel strength to lift the copper sheet at one end of the circuit pattern and fix it on the clip of the instrument for measuring peel strength, reset the tension of the instrument for measuring peel strength to zero, start the instrument for measuring peel strength, and slowly raise the clip until the circuit pattern is completely peeled off from the substrate. Record the tension value required in this process and calculate the peel strength, wherein the peel strength = tension (N) / line width (mm).

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention designs a method for measuring the bonding strength of copper plating, and accurately measures the specific value of the bonding strength of copper plating through a peel strength test, thereby realizing the quantification of the bonding strength of copper plating, and providing a scientific basis for the quality in the production process; and the present application uses a standardized peel strength measuring instrument and the same operating steps, which reduces the interference of human factors and improves the accuracy and repeatability of the test results; at the same time, the measurement method proposed by the present invention does not need to destroy the sample, and multiple tests can be performed on the same board, which reduces the waste of samples, saves costs and improves the utilization rate of resources.

[0012] In the above method, the base copper thickness of the copper clad laminate mentioned in step S1 is 18-35 μm.

[0013] In the above method, the width and length of the copper clad laminate mentioned in step S1 are both greater than or equal to 30 μm.

[0014] In the above method, the width of the circuit pattern mentioned in step S3 is 1 to 5 mm, and the length is 15 to 25 cm.

[0015] In the above method, the instrument for measuring the peel strength mentioned in step S4 includes but is not limited to an electronic peel strength tester.

[0016] In the above method, the acceptable range of the peel strength mentioned in step S4 is 0.3 to 1.0 mm.

[0017] In the above method, the circuit pattern mentioned in step S3 is a plurality of rectangles, and the rectangles are regularly arranged on the substrate.

[0018] The above method also includes the following steps: S5: When the peel strength is less than 0.3N / mm, the production line is checked for abnormalities.

[0019] The above method is suitable for evaluating the bonding strength of copper plating under different types of copper plating solutions, substrates of different materials and different processing parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the method steps for measuring the bonding strength of copper plating according to an embodiment of the present invention;

[0021] Figure 2 Schematic diagram of the structure of the substrate and the circuit pattern in step S3 of an embodiment of the present invention.

[0022] Description of the accompanying drawings: 100 substrate, 110 circuit pattern. DETAILED DESCRIPTION

[0023] The embodiments of the present invention are described in detail below. Figure 1 to Figure 2 , an embodiment of the present invention provides a method for measuring the bonding strength of copper plating, comprising the following steps:

[0024] S1: A basic copper clad laminate is selected, and the copper foil on the surface of the copper clad laminate is etched to retain the substrate 100 of the copper clad laminate.

[0025] S2: copper is deposited on the substrate 100, and the copper backlight is ≥ level 9 by using vertical copper deposition or horizontal copper deposition. After copper deposition, electroplating is performed, and the thickness of the electroplated copper layer is 30-35 μm.

[0026] S3: forming a circuit pattern 110 on the substrate 100 after the above step S2;

[0027] S4: Use an instrument for measuring peel strength to lift the copper sheet at one end of the circuit pattern 110 and fix it on the clip of the instrument for measuring peel strength. Return the tension of the instrument for measuring peel strength to zero, start the instrument for measuring peel strength, and slowly raise the clip until the circuit pattern 110 and the substrate 100 are completely peeled off. Record the tension value required in this process and calculate the peel strength. Peel strength = tension (N) / line width (mm).

[0028] The present invention designs a method for measuring the bonding strength of copper plating, and accurately measures the specific value of the bonding strength of copper plating through a peel strength test, thereby realizing the quantification of the bonding strength of copper plating, and providing a scientific basis for the quality in the production process; and the present application uses a standardized peel strength measuring instrument and the same operating steps, which reduces the interference of human factors and improves the accuracy and repeatability of the detection result; at the same time, the measurement method proposed by the present invention does not need to destroy the sample, and multiple tests can be performed on the same board, which reduces the waste of samples, saves costs and improves the utilization rate of resources.

[0029] Further, the base copper thickness of the copper clad foil board mentioned in step S1 is 18-35 μm, which ensures the applicability and consistency of the substrate 100, and helps to improve the measurement accuracy and reliability of the copper deposition bonding force. Preferably, the base copper thickness is 25 μm; further, the width and length of the copper clad foil board mentioned in step S1 are both greater than or equal to 30 μm. By stipulating the minimum size of the copper clad foil board, sufficient area of ​​the test sample is ensured, which is convenient for multiple tests and data comparison, and improves the accuracy and repeatability of the test results; further, the width of the circuit pattern 110 mentioned in step S3 is 1-5 mm, and the length is 15-25 cm. By limiting the size range of the circuit pattern 110, the standardization of the test pattern is ensured, which is convenient for precise measurement using a peel strength tester, and improves the accuracy and repeatability of the test results. Of course, the present invention does not limit the specific shape of the circuit pattern 110. Preferably, refer to Figure 2 The circuit pattern 110 mentioned in step S3 is a plurality of rectangles, and the rectangles are regularly arranged on the substrate 100 .

[0030] Furthermore, the instrument for measuring the peel strength mentioned in step S4 includes but is not limited to an electronic peel strength tester. Preferably, the instrument for testing the peel strength proposed in the present invention adopts an electronic peel strength tester. The commonly used electronic peel strength tester includes a fixture and a control panel; the fixture includes an upper clamp and a lower clamp. When testing the circuit pattern 110, first, the copper sheet at one end of the circuit pattern 110 is picked up, and the picked copper sheet is fixed on the upper clamp of the electronic peel strength tester, and the entire substrate 100 is fixed on the lower clamp, and then the tension of the electronic peel strength tester is reset to zero on the control panel, and then the start button on the control panel is operated to start the electronic peel strength tester. At this time, as the upper clamp slowly rises, the circuit pattern 110 and the substrate 100 are peeled off. The peel strength of the circuit pattern 110 can be calculated by measuring the force required for the peeling process. By setting the calculation formula of the peel strength, peel strength = tension (N) / line width (mm), the difference in the bonding force of the copper plating can be directly reflected by the data of the peel strength measurement. Furthermore, the qualified range of the peel strength mentioned in step S4 is 0.3~1.0mm, and the traditional test method can only provide qualitative results, that is, qualified or unqualified, and lacks specific numerical standards. The present application provides a clear numerical standard for the evaluation of the bonding strength of copper plating by setting the qualified range of peel strength to 0.3~1.0mm. This makes the quality control in the production process more scientific and precise, and avoids the inconsistency and uncertainty caused by subjective judgment. At the same time, the present test method also includes the following steps: S5: When the peel strength is less than 0.3N / mm, the production line is checked for abnormalities; by checking for abnormalities when the peel strength is lower than the qualified range, potential quality problems can be discovered in the early stages of production, product failure due to insufficient bonding strength of copper plating can be avoided, and product reliability and production efficiency can be improved. Furthermore, the method for measuring the copper bonding strength proposed by the present invention is applicable to the copper bonding strength evaluation under different types of copper bonding solutions, substrates 100 of different materials and different processing parameters. The traditional method cannot effectively evaluate the influence of different copper bonding solutions, substrates 100 of different materials and different processing parameters on the copper bonding strength. The method provided by the present invention is applicable to a variety of copper bonding solutions, substrates 100 of different materials and different processing parameters, and can comprehensively evaluate the influence of these factors on the copper bonding strength. This provides a scientific basis for optimizing the production process and ensures the product quality under different conditions; and by quantitatively measuring the copper bonding strength, the influence of different copper bonding solutions, substrates 100 of different materials and different processing parameters on the copper bonding strength can be systematically evaluated, thereby selecting the best process parameters, optimizing the production process, and improving production efficiency and product quality.

[0031] It should be noted that in the description of the present invention, if there are any orientation descriptions, such as up, down, front, back, left, right, etc., the orientations or positional relationships indicated are all based on the orientations or positional relationships shown in the drawings. They 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 or operated in a specific orientation, and cannot be understood as a limitation on the present invention.

[0032] In the description of the present invention, the meaning of "several" is one or more, the meaning of "more" is two or more, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there is a description of the first method of measuring the bonding strength of copper plating or the second method, it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0033] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0034] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A method for measuring the bonding strength of copper plating, characterized in that: The following steps are involved: S1: selecting a basic copper-clad laminate, and retaining the base material (100) of the copper-clad laminate by etching the copper foil on the surface of the copper-clad laminate; S2: depositing copper on the substrate (100) by using vertical copper deposition or horizontal copper deposition to make the copper deposition backlight ≥ level 9, and then electroplating after copper deposition, wherein the thickness of the electroplated copper layer is 30 to 35 μm; S3: making a circuit pattern (110) on the substrate (100) after the above step S2; S4: Using an instrument for measuring peel strength, lift up the copper sheet at one end of the circuit pattern (110) and fix it on the clip of the instrument for measuring peel strength, reset the tension of the instrument for measuring peel strength to zero, start the instrument for measuring peel strength, and slowly raise the clip until the circuit pattern (110) and the substrate (100) are completely peeled off, record the tension value required in this process, and calculate the peel strength, wherein the peel strength = tension (N) / line width (mm).

2. The method according to claim 1, characterized in that The base copper thickness of the copper clad laminate mentioned in step S1 is 18-35 μm.

3. The method according to claim 1, characterized in that The width and length of the copper clad laminate mentioned in step S1 are both greater than or equal to 30 μm.

4. The method according to claim 1, characterized in that: The circuit pattern (110) mentioned in step S3 has a width of 1 to 5 mm and a length of 15 to 25 cm.

5. The method according to claim 1, characterized in that: The instrument for measuring the peel strength mentioned in step S4 includes but is not limited to an electronic peel strength tester.

6. The method according to claim 1, characterized in that The acceptable range of the peel strength mentioned in step S4 is 0.3 to 1.0 mm.

7. The method according to claim 1, characterized in that The circuit pattern (110) mentioned in step S3 is a plurality of rectangles, and the rectangles are regularly arranged on the substrate (100).

8. The method according to claim 1, characterized in that The following steps are also included: S5: When the peel strength is less than 0.3 N / mm, the production line is checked for abnormalities.

9. The method according to claim 1, characterized in that: The invention is suitable for evaluating the bonding strength of copper plating under different types of copper plating solutions, substrates of different materials (100) and different processing parameters.

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