Design for testability for wafer-scale integration interconnect systems design and test methodology

A novel test approach for interconnects of laser configurable wafer-scale integration (WSI) systems is described. In this approach, buses are terminated by registers-called Echoregisters-which receive and reflect test signals. The test is carried out in the form of an echo and is therefore called Echotest. The test of the interconnect system is of crucial significance for WSI, because of the extensive interconnect systems that cover a large part of the chip area. Stuck-at, stuck-open, and stuck-on faults, including opens and shorts in the interconnect systems, which are assumed to include amplifiers, can be detected with the described Echotest. By this procedure it is sufficient to access the device under test by only one end. The hardware is half of that of a scan path, as used for the usual tests. The test hardware is realized in an experimental chip