Reliability and High-Frequency Filter Characteristics of a Low-Loss Material for 5G RF Modules

With the tremendous advances and increasing demand in 5G communications, the low-loss performance of RF device components becomes more critical. Two parameters that have significant impact on the low-loss RF performance are lower circuit conductor loss and dielectric loss of the build-up materials. Therefore, this study is focused on the loss tangent (Df) of the dielectric build-up material and demonstration of its electrical reliability with a low-loss substrate for high-frequency transmission. This newly developed advanced low-loss dry film build-up material exhibits a Dfvalues of < 0.003 at 39 GHz and is applicable to high frequency transmission. This build-up material also exhibits excellent electrical reliability required for advanced dielectric materials. For evaluation of the filter characteristics in the mm Wave band, a substrate with filter circuit structures was fabricated using the low loss dielectric material. Transmission characteristics of the filters were measured and demonstrated to have a minimum transmission loss of less than 1.18 dB at 39 GHz.