Accurate method for determination of interconnect cross section

Several experimental studies reported an increase of the copper resistivity with decreasing interconnects dimensions (Schafft and Suchle, 1992). However, the accuracy of measurement is limited by the knowledge of sample geometry. As a matter of fact, the geometry of resistors issued from advanced damascene process is varying with process parameters (trench height, diffusion barrier thickness, CMP (chemical mechanical polishing) effect). Taking into consideration Mathiessen empirical relation we established a relation between, resistivity, TCR (temperature coefficient of resistance) and metal cross section to develop an accurate methodology to determine thickness and resistivity of damascene copper samples.