Electronic Scanning in Acoustic Microscopy

Scanning acoustic microscopy (SAM) employs mechanical scanning in both x and y directions. There is one great advantage in this configuration which is that imaging is done on axis, resulting in diffraction limited resolution. However a mechanical system is inherently slow and cumbersome, even though recent advances have brought the scanning time for an image at high frequencies down to the order of a second. For the inspection of inexpensive items such as integrated circuit chips, which is done at frequencies below 100 MHz, it is imperative to have a cheap and ideally real time system. The present work describes recent developments in our laboratory in this directio