A Case Study of the Impact of Fabrication Processes on PCB Broadband Electrical Characteristics

It is well-known that copper foil roughness, dielectric constant, and loss tangent of materials are critical factors to high frequency electrical characteristics. These parameters may not be fixed values; they can vary with the frequency as well as PCB fabrication processes. In this paper, the electrical impacts of prepreg moisture absorption and copper foil roughness imparted by adhesion promotion treatments were studied. The broadband electrical characteristics of the PCBs were evaluated by Short Pulse Propagation (SPP) test method [1] [2].