关键词: 数值模拟, 通孔电镀, 周期换向脉冲电镀, 均镀能力, 正交实验

Abstract:

The upgrade of the fifth generation (5G) communication technology increases the number of communication backplane layers and the aspect ratio of through holes on the board, making it more difficult to use traditional direct current deposition for interconnection. Direct current electrodeposition is more prone to uneven coating in the hole, resulting in poor contact between the coating and components, and open circuit. This has a serious impact on the stability of printed circuit board. The periodic pulse reverse plating method can significantly improve the uniformity of high aspect ratio through-hole plating and improve the production quality of through-hole plating through the dissolution and electromigration of the coating in the reverse pulse process. Compared with direct current method, periodic reverse pulse has multiple controllable parameters. Changing these parameters will have different effects on the quality of through-hole electroplating. However, to study all parameters one by one, the number of experiments is huge and time-consuming. Numerical simulation is a newly developing research method, which intuitively studies the influence of a variety of physical fields. And it can be completed only by calculation, which avoids the loss of a large number of experiments. In this work, the influences of periodic pulse reverse parameters in through hole electroplating were studied by numerical simulation. Based on the orthogonal experiments, the influence order and rule of the periodic pulse reverse parameters on throwing power (TP) of through hole were analyzed. Among them, the reverse pulse duty ratio has a great influence on the TP of through-hole. The optimal combination is screened as: Forward peak current density 1 A·dm^-2, ratio of positive and reverse peak current density 1:4, reverse peak width 1ms, ratio of positive and reverse peak width 30:1, forward duty cycle 1, reverse duty cycle 1, number of forward peak 2, number of reverse peak 3. Using the optimized parameter combination in the simulation results, TP is greatly improved as compared with direct current electrodeposition. The parameters of periodic pulse reverse electroplating optimized by numerical simulation method can effectively improve the uniform plating capacity of through holes, and can be applied to actual electrodeposition of through holes. Using the optimized parameters, the TP of through hole with the aspect ratio of 1:10 is improved efficiently. The experimental results provide theoretical support and new ideas for the optimization of periodic pulse reverse electroplating by numerical simulation method.

Key words: numerical simulation, through hole electroplating, periodic pulse reverse electroplating, throwing power, orthogonal test