A Study of the Influence of Microstructure, Nodulation and Barrier on Signal Integrity

The signal transmission characteristics of copper foil used in high-frequency and high-speed circuits depend on its surface roughness, microstructure and barrier. This study presents the influence of copper foil manufacturing process on the insertion loss of printed circuit board (PCB) in high-frequency circuit applications. In order to meet the increasing heat resistance requirement of high-frequency and high-speed prepregs, a new barrier design is also presented in this study. Experimental results indicated that a new surface treatment technique used in the preparation of a ultra-low roughness copper foil (VH0 foil) with good adhesion strength, equivalent to high roughness copper foil (TLC-V1 foil), and excellent heat resistance. In addition, low insertion loss over 10 GHz band due to this ultra-low roughness, less crystalline defects and good conductivity of conductor line was also demonstrated by this new processing technique.