NONDESTRUCTIVE THICKNESS DETERMINATION OF THIN COBALT AND COBALT DISILICIDE LAYERS ON SILICON SUBSTRATES

The thickness of thin cobalt and cobalt disilicide layers has been mea sured by spectroscopic ellipsometry (SE). The results obtained by this non-destructive technique are compared with measurements done by two well-established but destructive techniques, namely Rutherford backsca ttering spectrometry (RBS) and high resolution transmission electron m icroscopy (HREM). The thickness values obtained by SE are in good agre ement with the values measured by RBS and HREM. Spectroscopic ellipsom etry allows one to determine the thickness of the metal and silicide l ayers on device wafers, thereby avoiding the need to use destructive t echniques on test wafers or fully processed device wafers.