Reducing Crosstalk: Area signal traces properly and use floor planes to protect towards interference. On the other hand, there is only one layer of copper on a single-sided board, which often can only be used for format, plus the holes made can only be useful for SMT. Prepreg (pre-impregnated) and https://six-layer-high-frequency61593.activosblog.com/30533985/5-simple-statements-about-hdi-arbitrary-interconnect-pcb-for-pico-projector-explained