A technique for manufacturing a circuit board involves obtaining a plane-shaped structure having layers of circuit board material integrated together, and carving a hole within the plane-shaped structure (e.g., using a single countersinking drill bit). The carved hole includes an inner portion having...http://www.google.fr/patents/US7155821?utm_source=gb-gplus-shareBrevet US7155821 - Techniques for manufacturing a circuit board having a countersunk via
Techniques for manufacturing a circuit board having a countersunk via
