A space-saving test structure includes a core metal line, at least one extrusion
detection line and an extrusion monitoring segment. The core metal line has a "non-linear
configuration" and is capable of conducting current for an electromigration test,
an isothermal test, and extrusion monitoring. The at least one extrusion detection
line is situated adjacent to the core metal line. The extrusion monitoring segment
is electrically connected to the at least one extrusion detection line. The extrusion
monitoring segment is adapted to determine whether an extrusion occurs in the core
metal line by measuring a resistance between the core metal line and the at least
one extrusion detection line.
