Ultra high density interconnect (UHDI) PCBs are changing the game in designing for the reality of manufacturing. With both consumer and industrial electronic devices becoming more advanced, the demand for UHDI PCBs will grow. That means we’re all likely to be designing more UHDI boards. UHDI advanced miniaturization technology challenges designers with regard to both board thickness and footprint. Designers will face more variables in every aspect of design creation. This is certainly the case with drilling.

Drilling is already one of the more complex and tricky steps in the manufacturing process. Designers must consider everything from board thickness and via size to material type to craft their designs and avoid problems during drilling that can drive up costs and increase the risk of board performance issues. With UHDI designs there is a lot for the designer to consider.

A Quick Refresher on Sound Drilling Practice

Drilling follows lamination in the multilayer PCB board manufacturing process. Once the lamination process is complete, we have a book—a stack of panels manufactured into a multilayer PCB. Panel preparation takes place before drilling can begin. After cleaning, we remove the flash around the edges to create a perfect rectangle that can be handled safely.

To ensure drilling accuracy, we use a test coupon. The coupon contains drill targets for each layer, and the movement of the layer from nominal can be calculated using an X-ray on each layer, hitting all connections and missing clearances.