Circuit board and manufacturing method thereof

A circuit board, comprising:

• a circuit board plate comprising a surface and a conductive through hole passing through the surface and the circuit board plate, wherein the conductive through hole have a conductive layer disposed on a wall thereof;
• a conductive ring disposed on the surface, wherein the conductive ring surrounds an opening of the conductive through hole located on the surface and electrically connects to the conductive layer;
• a solder mask disposed on the surface, wherein the conductive ring is exposed outside of the solder mask;
• and
• at least one insulating pad comprising a first surface and a second surface opposite to each other and having a thickness, wherein the first surface is adapted to contact the solder mask or the surface of the circuit board plate and sited at periphery of the conductive ring, the second surface is adapted to contact a solder coating tool when the solder coating tool is covered on the circuit board thereby spacing a distance between the solder coating tool and the solder mask, wherein the at least one insulating pad is a closed ring, the conductive ring is located within the closed ring, and the at least one of the insulating pad surrounds a corresponding plurality of the conductive rings.