<p>A read only memory is manufactured with a plurality of transistors (4) on a semiconductor substrate (2). A low-k dielectric (10) and interconnects (14) are provided over the transistors (4). To program the read only memory, the low-k dielectric is implanted with ions (22) in unmasked regions (20) leaving the dielectric unimplanted in masked regions (18). The memory thus formed is difficult to reverse engineer.</p>
