CN-122016425-A - Method for detecting surface components of copper foil of FPC flexible circuit board

CN122016425ACN 122016425 ACN122016425 ACN 122016425ACN-122016425-A

Abstract

The invention discloses a method for detecting surface components of a copper foil of an FPC flexible circuit board, which comprises the following steps of S1, providing an electrolytic copper foil to be detected, superposing a non-detection surface of the electrolytic copper foil and an epoxy resin prepreg to form a composite board, S2, cutting the composite board to obtain a sample, S3, soaking the sample in 60 ℃ ultrapure water, uniformly spraying a solution of nitric acid and water with a volume ratio of 1:1 to the detection surface of the electrolytic copper foil, repeating for 2-3 times, immediately flushing a solution of the detection surface of the electrolytic copper foil with the ultrapure water, collecting all the obtained mixed solution into a polytetrafluoroethylene beaker, S4, transferring the collected solution into a volumetric flask, shaking uniformly after the volumetric flask is fixed with the ultrapure water to obtain the liquid to be detected, and S5, detecting the liquid to be detected by detection equipment. According to the method, through single-sided dissolution stripping and directional collection, independent detection of components on the single-sided surface of the electrolytic copper foil is realized, and single-sided accurate analysis of the electrolytic copper foil is further completed.

Inventors

LI SHOUYUN
LI XIAOWEI

Assignees

联决电子科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260205

Claims (8)

1. The method for detecting the surface components of the copper foil of the FPC flexible circuit board is characterized by comprising the following steps of: S1, providing an electrolytic copper foil to be tested, and superposing a non-detection surface of the electrolytic copper foil and an epoxy resin prepreg to form a composite board; s2, cutting the composite board to obtain a sample; S3, soaking the sample in 60 ℃ ultrapure water, uniformly spraying a solution of nitric acid and water with a volume ratio of 1:1 on the detection surface of the electrolytic copper foil, repeating for 2-3 times, immediately flushing the solution on the detection surface of the electrolytic copper foil with the ultrapure water, and collecting all the obtained mixed solution into a polytetrafluoroethylene beaker; S4, transferring the collected liquid to a volumetric flask, and shaking uniformly after the volume is fixed by ultrapure water to obtain liquid to be measured; S5, detecting the liquid to be detected by adopting detection equipment.
2. The method for detecting the surface components of the copper foil of the FPC flexible circuit board according to claim 1, wherein the thickness of the electrolytic copper foil to be detected in S1 is 10-210 μm.
3. The method for detecting the surface components of the copper foil of the FPC flexible circuit board according to claim 1, wherein the preparation of the composite board in S1 comprises the following steps: S1.1, prefabricating network-shaped micro grooves and a plurality of micron-sized blind holes arranged in an array on a non-detection surface of an electrolytic copper foil to be detected by utilizing a laser or etching technology, and simultaneously coating a layer of epoxy resin film at the bottoms of the micro grooves and the blind holes, wherein soft magnetic particles are dispersed in the epoxy resin film; S1.2, providing an epoxy resin prepreg, which comprises an epoxy resin matrix, soft magnetic particles uniformly dispersed in the epoxy resin matrix and magnetic sealing microcapsules wrapped with low-viscosity sealing resin; s1.3, stacking the epoxy resin prepreg and the electrolytic copper foil to be tested, and enabling a non-detection surface of the electrolytic copper foil to be tested to be in contact with the epoxy resin prepreg; S1.4, heating the stacked components to enable the epoxy resin prepreg to be molten to be in a viscous flow state; S1.5, applying an alternating magnetic field to the assembly, wherein the alternating magnetic field drives soft magnetic particles to move, so that molten epoxy resin is promoted to fill the blind holes and the micro grooves, meanwhile, magnetic sealing microcapsules are guided to migrate to the surface of the copper foil and are concentrated in the micro grooves, the magnetic sealing microcapsules are gathered and collided in the micro grooves and are broken under the micro vibration and local thermal effect generated by the magnetic field, and low-viscosity sealing resin flows out to fill the micro grooves; S1.6, maintaining the alternating magnetic field until the epoxy resin is solidified, and forming a sealing layer of a mechanical interlocking structure between the electrolytic copper foil to be tested and the solidified epoxy resin layer.
4. The method for detecting the surface components of the copper foil of the FPC flexible circuit board according to claim 3, wherein the blind holes in S1.1 are in an inverted cone shape or a bowl shape, and the cross section of the micro grooves is in an inverted cone shape.
5. The method for detecting the surface components of the copper foil of the FPC flexible circuit board according to claim 3, wherein the soft magnetic particles in S1.1 are nickel zinc ferrite.
6. The method for detecting the surface components of the copper foil of the FPC flexible circuit board according to claim 3, wherein the shell of the magnetic sealing microcapsule in the S1.2 is a composite thin layer of a nanoscale soft magnetic material and a polymer, and the shell is driven to drive the whole magnetic sealing microcapsule to move under the action of an alternating magnetic field.
7. The method for detecting the surface composition of the copper foil of the FPC flexible circuit board according to claim 3, wherein the heating temperature in S1.4 is 160-180 ℃.
8. The method for detecting the surface composition of the copper foil of the flexible printed circuit board of the FPC according to claim 3, wherein the step of applying the alternating magnetic field in S1.5 comprises the steps of: firstly, applying a first magnetic field parameter to drive molten epoxy resin to fill the blind holes and the micro grooves; A second magnetic field parameter is then applied to drive the migration and enrichment of the magnetically sealed microcapsules in the microchannel.

Description

Method for detecting surface components of copper foil of FPC flexible circuit board Technical Field The invention relates to the technical field of copper foil detection methods, in particular to a method for detecting surface components of a copper foil of an FPC flexible circuit board. Background Flexible printed circuit boards (Flexible Printed Circuit, abbreviated as FPCs) are widely used in modern electronic devices, and electrolytic copper foil is generally used as a core conductive layer. The chemical composition of the surface of the electrolytic copper foil, especially trace or trace amounts of additive elements, residual treating agents and pollutants, has a key influence on the subsequent adhesion strength, etching performance, oxidation resistance and overall circuit reliability. Therefore, the development of an accurate and efficient copper foil surface component detection method has important significance for FPC material quality control, process optimization and failure analysis. Traditional detection methods (such as full foil dissolution) cannot distinguish the composition differences on both sides of the copper foil, resulting in masking of critical surface defects. At present, in the industry, two components of a double-sided copper foil are different in an electrolysis and coating process, the existing method cannot realize single-sided accurate analysis, and a standardized method is not used for quantifying the components of the single-sided surface of the copper foil. Disclosure of Invention The invention aims to solve the problem of providing the method for detecting the surface components of the copper foil of the FPC flexible circuit board, which realizes independent detection of the single-side surface components of the electrolytic copper foil through single-side dissolution stripping and directional collection, and further completes single-side accurate analysis of the electrolytic copper foil. The invention provides a method for detecting the surface components of a copper foil of an FPC flexible circuit board, which comprises the following steps: S1, providing an electrolytic copper foil to be tested, and superposing a non-detection surface of the electrolytic copper foil and an epoxy resin prepreg to form a composite board; s2, cutting the composite board to obtain a sample; S3, soaking the sample in 60 ℃ ultrapure water, uniformly spraying a solution of nitric acid and water with a volume ratio of 1:1 on the detection surface of the electrolytic copper foil, repeating for 2-3 times, immediately flushing the solution on the detection surface of the electrolytic copper foil with the ultrapure water, and collecting all the obtained mixed solution into a polytetrafluoroethylene beaker; S4, transferring the collected liquid to a volumetric flask, and shaking uniformly after the volume is fixed by ultrapure water to obtain liquid to be measured; S5, detecting the liquid to be detected by adopting detection equipment. Preferably, the thickness of the electrolytic copper foil to be tested in the step S1 is 10-210 μm. Preferably, the preparation of the composite board in S1 includes the following steps: S1.1, prefabricating network-shaped micro grooves and a plurality of micron-sized blind holes arranged in an array on a non-detection surface of an electrolytic copper foil to be detected by utilizing a laser or etching technology, and simultaneously coating a layer of epoxy resin film at the bottoms of the micro grooves and the blind holes, wherein soft magnetic particles are dispersed in the epoxy resin film; S1.2, providing an epoxy resin prepreg, which comprises an epoxy resin matrix, soft magnetic particles uniformly dispersed in the epoxy resin matrix and magnetic sealing microcapsules wrapped with low-viscosity sealing resin; s1.3, stacking the epoxy resin prepreg and the electrolytic copper foil to be tested, and enabling a non-detection surface of the electrolytic copper foil to be tested to be in contact with the epoxy resin prepreg; S1.4, heating the stacked components to enable the epoxy resin prepreg to be molten to be in a viscous flow state; S1.5, applying an alternating magnetic field to the assembly, wherein the alternating magnetic field drives soft magnetic particles to move, so that molten epoxy resin is promoted to fill the blind holes and the micro grooves, meanwhile, magnetic sealing microcapsules are guided to migrate to the surface of the copper foil and are concentrated in the micro grooves, the magnetic sealing microcapsules are gathered and collided in the micro grooves and are broken under the micro vibration and local thermal effect generated by the magnetic field, and low-viscosity sealing resin flows out to fill the micro grooves; S1.6, maintaining the alternating magnetic field until the epoxy resin is solidified, and forming a sealing layer of a mechanical interlocking structure between the electrolytic copper foil to be tested and the solidified epox