Three-dimensional circuit board, manufacturing method thereof, and probe card

A probe card, comprising:

• a three-dimensional circuit board, comprising:
• a ceramic substrate, having a first plane, a second plane, a third plane located between the first plane and the second plane, a first side surface connecting the first plane and the second plane, and a second side surface connecting the first plane and the third plane and opposite to the first side surface, wherein a first height of the first side surface is greater than a second height of the second side surface, and the third plane and the second side surface form a groove;
• and
• a plurality of circuits, separately embedded on the first plane of the ceramic substrate and extending along the first side surface to be embedded on the second plane, wherein an arrangement density of the circuits on the first plane is greater than an arrangement density on the second plane;
• a printed circuit board, disposed on the second plane of the three-dimensional circuit board and electrically connected to the plurality of the circuits;
• and
• a probe structure, comprising a cantilever and a needle, wherein the cantilever has a fixed end and a free end, the fixed end is disposed on the first plane and is connected to the circuits, the needle is connected to the free end, and there is an air gap between the cantilever and the third plane.