Study on the influence of precise control of temperature, pH value, and current density of copper plating solution on the quality of coating

Coating copper layer on polyimide (PI) film is one of the key processes for manufacturing high-performance flexible circuit boards. The quality of the coating directly affects the reliability and service life of the final product. This article explores the influence of factors such as temperature, pH value, and current density of copper plating solution on the quality of coating through experimental data, and introducesAdvanced Institute (Shenzhen) Technology Co., LtdResearch achievements in precise control of these parameters.

Polyimide film has a wide range of applications in flexible circuit boards (FPCs) due to its excellent electrical properties, heat resistance, and mechanical strength. However, forming a uniform and dense copper layer on the surface of PI thin films is a technical challenge, especially in the trend of pursuing thinner and more uniform coatings. The precise control of parameters such as temperature, pH value, and current density of copper plating solution has become the key to improving the quality of the coating.

Experimental Design and Methods

To investigate the effects of temperature, pH value, and current density on copper plating solutionPI thin film copper plating layerThe impact on quality was studied using the following methods in the experiment:

• Experimental materials: Standard PI film is selected as the substrate, and a copper plating solution containing copper sulfate, sulfuric acid, chelating agent, brightener and other components is prepared.
• Experimental instruments: standard laboratory equipment such as constant temperature water bath, pH meter, DC power supply, etc.
• Experimental steps: Conduct copper plating experiments under different temperature, pH, and current density conditions, and record the thickness, surface morphology, and other characteristics of the coating.

The Influence of Temperature on Coating Quality

Temperature is an important factor affecting the crystallization state and growth rate of coatings. The experimental results show that when the temperature of the plating solution is controlled at 45 ° C, the crystallization of the coating is uniform and dense, and the surface roughness is the smallest, about 0.05 μ m. As the temperature increases, although the growth rate of the coating accelerates, when it exceeds 50 ° C, the coating begins to exhibit grain coarsening and unevenness, which affects the overall quality of the coating.

The Influence of pH Value on Coating Quality

The pH value is a key parameter for regulating the state of copper ions in the plating solution. Experiments have found that the deposition rate and uniformity of the coating are optimal when the pH value is maintained between 4.5 and 5.5. Excessive or insufficient pH values can cause defects on the surface of the coating, such as pinholes or cracks. Especially when the pH value is below 4.0, the surface of the coating is prone to forming a loose structure, which is not conducive to subsequent processing.

The Influence of Current Density on Coating Quality

The current density directly affects the reduction rate of metal ions and the uniformity of the coating. Experimental data shows that at a current density of 1.5A/dm ², the growth rate of the coating is moderate, the grain size is fine, and the surface is smooth. Excessive current density (greater than 2.5A/dm ²) can lead to dendritic crystals on the surface of the coating, while insufficient current density (less than 1.0A/dm ²) can slow down the growth of the coating and affect production efficiency.

Research achievements of Advanced Institute (Shenzhen) Technology Co., Ltd

Advanced Institute (Shenzhen) Technology Co., Ltd. has conducted in-depth research on the precise control of copper plating process parameters and has achieved a series of results:

• Intelligent control system: A set of intelligent control system based on Internet of Things technology has been developed, which can monitor and automatically adjust the temperature, pH value, and current density of copper plating solution in real time, ensuring that these parameters are always within the optimal range.
• Experimental data: Through the application of this system, the thickness deviation of the coating is controlled within ± 5%, and the uniformity and density of the coating are significantly improved.
• Technical improvement: By introducing advanced additives and optimizing the plating solution formula, the adhesion and corrosion resistance of the coating have been further enhanced.

conclusion

By precisely controlling key parameters such as temperature, pH value, and current density of the copper plating solution, significant improvements can be achievedPI thin film copper platingThe quality of the layer. The research results of Advanced Institute (Shenzhen) Technology Co., Ltd. demonstrate the potential in optimizing copper plating processes and provide valuable experience and technical support for the industry.

The above data is for reference only, and specific performance may vary due to production processes and product specifications.