In this technique, the component side of the board is dedicated to the ground plane, and signal traces are placed on the solderside.
采用这种技术时，电路板的元件侧专用于接地层，信号走线则布设在焊接侧。
3
If this bump is soldered to the pad on a packaging substrate, solder gets wet in the whole region of the columnar bump upper surface and only a part of the side surface.