A security tag for electronic designs implemented on integrated circuits uses a thermal transmitter to transmit tag data to an external sensor. Some embodiments include swapping cells to improve routing. The etch stop can alternatively be made by pulsing the RF field in either a PECVD process or an LPCVD process. The openings are in communication with one another and adapted for permitting for the growth of bone from adjacent vertebral body to adjacent vertebral body through the implant.