Research on the influence of electroplating lines on the transmission performance of ceramic package

In the field of highly reliable ceramic package, in order to realize chip sintering and gold wire bonding, the surface coating of the package is generally achieved by electroplating process. In order to realize the electroplating of the surface pattern of the package, it is necessary to introduce an auxiliary electroplating line on the basis of the original signal line. In this paper, the influence of electroplating wire on the RF performance and transmission characteristics of the signal wire of ceramic package is studied to improve the electrical performance design ability of the package. This paper mainly studies the influence of electroplating lines with different length and width and the position of electroplating lines on the RF performance and transmission characteristics of signal lines, determines the influence degree of electroplating lines on signal lines, forms design rules, and defines the applicable scope of electroplating lines. By changing the length, width and position of the electroplating line, different simulation models are established, and HFSS simulation software is used to study and analyze the influence of the electroplating line on the S parameters and impedance of the signal line in the frequency range of DC~10GHz. The results show that the impedance of the signal line decreases and the RF performance decreases sharply with the increase of the electroplating line. The influence of the electroplating line can be ignored for the signal line with the transmission frequency below 500MHz. The width of the electroplating line has little effect on the RF performance of the signal line. During the wiring of key signal lines, it is suggested that the electroplating line should be set according to the corresponding process rules to increase the process redundancy. The closer the electroplated line is to the wiring ground plane layer, the more discontinuous the impedance, and the greater the impact on the RF performance of the signal line. It is recommended that the electroplated line be placed in the wiring layer away from the ground plane layer in priority during the wiring of key signal lines.