Registration Accuracy
X-ray target drilling provides the reference holes for automated optical inspection machines to align panels during subsequent processing steps. This x-ray target drilling relies on machine vision to detect copper features buried inside laminate layers. Optical systems locate these internal pads and command the spindle to drill precisely into the center of the underlying feature.
Failure to achieve alignment here results in registration errors that force the discarding of the entire printed circuit board.
Alignment Constraint
Target size limits the diameter of the drill bit during x-ray target drilling operations. Small targets restrict the tolerance window for machine positioning and spindle runout. Large targets allow for greater deviation but consume valuable space within the design footprint.
Drilling accuracy dictates the success of multilayer interconnections where layers must align to permit electrical continuity through vias.
Fabrication Requirement
Mechanical stability governs the throughput rate during x-ray target drilling tasks. Spindle vibration causes the bit to wander from the center point of the target pad. Manufacturers monitor the deviation between the drilled hole and the target center to ensure the product meets registration tolerances.
Proper calibration of the x-ray source and the detector assembly prevents the drift that leads to unusable circuit panels.
