A non-contact, non-destructive technique is presented for the width profiling of modulated current carrying microconductors. Based on the Mirage Effect, experimental results on a test sample are shown to be in excellent agreement with theory. In general the technique would give a reliable estimation of the thermal behaviour of interconnect lines. Possible applications could include failure prediction studies based on the 'electromigration' phenomenon, thermal management and reliability issues in printed circuit boards and multi-chip modules, etc.