Abstract: A back drilling processing method for a circuit board includes: obtaining a board to be back drilled, wherein the board includes a target signal layer and at least two conductive reference layers; drilling a through hole at a set position of the board, and obtaining an actually measured spacing between two conductive reference layers; in response to a hole to be back drilled being of a first type, determining a target back drilling depth; controlling a drilling bit to drill for the target back drilling depth towards the target signal layer; in response to the hole to be back drilled being of a second type, determining a target relative height of a back drilling end point relative to a machine; and controlling the drilling bit to drill for the target relative height towards the target signal layer. The back drilling does not drill through the target signal layer.

Abstract: The present disclosure provides a circuit board. The circuit board may include a number of stacked core boards each having a top surface. At least part core boards of the number of stacked core boards may include circuit layers at top surfaces thereof. A groove may be defined through the at least part core boards. A conductive material may be received in the groove configured to couple to the circuit layers of at least two core boards. A cross section of the groove may include a length in a first direction and a length in a second direction, and the length in the first direction may be greater than the length in the second direction. Electroplating solution may capable of contacting any portions of the groove to electroplate, to form the conductive material.

Abstract: The present disclosure provides a circuit board. The circuit board may include a number of stacked core boards each having a top surface. At least part core boards of the number of stacked core boards may include circuit layers at top surfaces thereof. A groove may be defined through the at least part core boards. A conductive material may be received in the groove configured to couple to the circuit layers of at least two core boards. A cross section of the groove may include a length in a first direction and a length in a second direction, and the length in the first direction may be greater than the length in the second direction. Electroplating solution may capable of contacting any portions of the groove to electroplate, to form the conductive material.