CHIP LEVEL FAULT LOCATION USING X-ALGORITHM

In board level testing the faults are usually isolated to a field repl acement unit (FRU) rather than to a single chip. In this paper a new a lgorithm, called the X-algorithm, is presented to locate a faulty chip in an FRU. The location patterns (LPs) which contain only one symbol X/(X) over bar are introduced. The trajectory of the X/(X) over bar pr opagation sensitises the faults in the FRU. Based on the test results the LPs can be generated easily. In the X-algorithm the X/(X) over bar propagation trajectory is analysed so that the faulty chip can be loc ated automatically. Preliminary results show that the algorithm is qui te effective, and it may not be necessary to exhaustively simulate wit h the LPs.