An integrated circuit for locating failure process layers. The circuit has a
substrate
with a scan chain disposed therein, having scan cells connected to form a series
chain. Each connection is formed according to a layout constraint of a minimum
dimension provided by design rules for an assigned routing layer. Since the connection
in the assigned routing layer is constrained to a minimum, the scan chain is vulnerable
to variations in processes relevant to the assigned routing layer. The scan chain
makes it easier to locate processes causing low yield rate of the scan chain.