| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the conventional vulnerability to false means which, after a shield line is partly disconnected or separated, would reconnect to the shield line via an alternate route not hindering physical analyses by FIB processing or other appropriate means or connect to the shield line from the outside via a conductor path as a bypass, thereby making a detection facility useless. <P>SOLUTION: A protective circuit is installed which has formed therein at least one shield line 5 wired so as to cover an area to be protected in a semiconductor device and having only one path from a start point to an end point, and includes a plurality of detectors 3 which, when an electrical signal is applied from a signal generator 2 to the shield line 5, detect a change in the applied electrical signal and output the change as a detection signal, the detectors 3 being disposed in distributed places so that the change in the electrical signal will be propagated in order. The detection signals are fed into a determination unit 4 in the order they were output, and the state of the shield line 5 is determined based on the output result of the detection signals and the order in which the detection signals were output, according to which a false detection signal A1 is output. That way, the protective circuit detects a false alteration in the shield line 5. <P>COPYRIGHT: (C)2012,JPO&INPIT |
