Abstract: A multi-layer circuit board includes first, second, third, fourth and fifth insulating substrates, first, second, third and fourth wiring layers, a ground wiring layer and a power wiring layer. The insulating substrates and the wiring layers are press-bonded to each other to form the circuit board with a thickness of about 1.6 mm. Each of the first and fifth insulating substrates has a thickness of 5.7±0.285 mil. Each of the second and fourth insulating substrates has a thickness of 8±0.4 mil. The third insulating substrate has a thickness of 24.6±1.23 mil. The first signal wiring layer has a first resistance with respect to the ground wiring layer. The second signal wiring layer has a second resistance with respect to the ground wiring layer and the power wiring layer. The third signal wiring layer has a third resistance with respect to the ground wiring layer and the power wiring layer. The fourth signal wiring layer has a fourth resistance with respect to the power wiring layer.