Drill to Copper

When designing flexible circuit board it is crucial to keep drill to copper in mind. That is, the distance between a hole (via or non-plated through hole (NPTH) and a copper feature. The flexible dielectric materials that are used to manufacture flex product are not as dimensionally stable as the standard rigid material (FR4). This material moves, shrinks and contracts during the manufacturing processes which makes drill to copper critical to a successful product.

Tighter hole to copper is possible, but usually requires a first article to measure the material movement. A longer lead time will be needed.