Patent ID: 8402648

Claim:
A fabrication method of a printed circuit board including a through hole constituted by a hole penetrating through front and rear surfaces of the printed circuit board, the fabrication method comprising: applying conductive material plating to an inner wall surface of the hole to form the through hole electrically connecting the front and rear surfaces of the printed circuit board; and removing the conductive material plated on the inner wall surface of the hole, at least at a portion between the front and rear surfaces of the printed circuit board, the removing is carried out to thereby fabricate a printed circuit board having the through hole which electrically isolates the front surface of the printed circuit board from the rear surface thereof, wherein the printed circuit board has a structure having a plurality of wiring layers laminated, and has a first line and a second line which are connected with the conductive material and which are provided in the plurality of wiring layers so that a wiring layer which includes the first line differs from a wiring layer which includes the second line, wherein the removing removes the conductive material between the first line and the second line, and wherein either of the first line and the second line is a third line which is provided in a high-speed signal wiring layer and the other is a fourth line which is provided in a low-speed signal wiring layer, the removing removes the conductive material so that a length of the conductive material from a contact of the third line conductive material to a circularly removed portion is shorter than a length of the conductive material from a contact of the fourth line with the conductive material to the circularly removed portion.