Back drilling depth determination method and circuit board processing method and system

The invention discloses a back drilling depth determination method and a circuit board processing method and system, and belongs to the technical field of circuit board manufacturing, and the method comprises the steps: obtaining the position information of a surface layer, a reference layer and a back drilling target layer corresponding to a to-be-back-drilled position, and obtaining the distance between the surface layer and the reference layer, and the distance between the reference layer and the back drilling target layer; before back drilling processing, the thickness variation of a surface layer corresponding to a to-be-back-drilled position is obtained; and the back drilling depth of the position to be subjected to back drilling is determined according to the distance between the surface layer and the reference layer, the distance between the reference layer and the back drilling target layer and the thickness variation. According to the back drilling depth determination method, back drilling depth err