Chip package and power module

A power module, comprising:

• a printed circuit board having a grounding region;
• and
• a chip package located on the grounding region of the printed circuit board, comprising:
• a high voltage withstanding substrate having a main body, a functional layer, and a grounding layer, the main body having a top surface and a bottom surface opposite the top surface, a through hole through the top surface and the bottom surface, and a sidewall surrounding the through hole, wherein the functional layer is made of a material comprising gallium nitride (GaN) and is located on the top surface, the grounding layer covers the bottom surface and the sidewall, and the grounding layer is located on the grounding region of the printed circuit board and is electrically connected to the grounding region;
• and
• a device chip located on the functional layer, and having a grounding pad facing the main body, wherein the grounding pad is in contact with the functional layer and is electrically connected to the grounding layer in the through hole, and the grounding pad is further located in the functional layer.