Semiconductor manufacturing, including the multistep fabrication of ICs and tedious assembly of PCBs, has been outsourced to untrusted regions due to globalization. This invites many problems particularly for PCBs, which are vulnerable to nondestructive methods of attack such as X-ray data collection and surface trace probing. In the case of ICs, high-z materials have proven to be an effective countermeasure to block or scatter X-rays, but PCBs, because of their larger dimensions, are more difficult to fully secure. In this paper, a framework for passively obfuscating the critical connections between components on PCBs is demonstrated. A proof of concept is presented whereby an EDA tool combining the small features of micro electromechanical systems with X-ray simulation and 3D manufacturing processes is used to iteratively optimize a PCB design to thwart reverse engineering and probing attacks.