Non‐Destructive Testing Using Picosecond Ultrasonics

Picosecond ultrasonics has become a widely used metrology tool in the semiconductor device industry. It provides an accurate method for the measurement of the thickness of thin films, can determine the quality of the bonding between a film and a substrate, and gives information about mechanical properties. We describe the development of this technology starting from work in the research laboratory and following through to the development of an automated instrument for use in computer chip fabrication.