Flip-chip bonding structure and circuit board thereof

A circuit board comprising:

• a light-transmissive substrate including a first surface and a second surface;
• a first circuit group disposed on the first surface and including a plurality of first leads, each of the plurality of first leads includes a first bonding portion and projects a first lead shadow on the second surface, there is a first gap between the adjacent first leads;
• a second circuit group disposed on the first surface and including a plurality of second leads, each of the plurality of second leads includes a second bonding portion and projects a second lead shadow on the second surface, there is a second gap between the adjacent second leads, and the second gap is not equal to the first gap;
• a boundary circuit disposed on the first surface and located between the first and second circuit groups, the boundary circuit projects a boundary circuit shadow on the second surface;
• and
• an identifying member located on the second surface, wherein the boundary circuit shadow and the identifying member are configured to be passed through by a vertical imaginary line.