FOCUSED ION-BEAM OBSERVATION OF GRAIN-STRUCTURE AND PRECIPITATES IN ALUMINUM THIN-FILMS

Reliability in very large scale integrated circuits is strongly dependent on the grain structure of the aluminum metallization used in interconnection between devices on a chip. Commonly used techniques for grain metrology require the use of time consuming sample preparation. Focused ion beam microscopy is well suited to studying grain size and structure because it needs little or no sample preparation and can give information about grain structure throughout the typical 0.5-1 mum thickness of aluminum films. Measurements of grain size and observations of precipitates in aluminum metallization by using focused ion beam are presented.