5. New Techniques and Phenomena
In this paper, the results of imaging experiments with the interfacial region~ of representative solid material joints, using a transmission-type scanning acoustic microscope operating at 150 MHz, are reported. Voids and flaws in specially made joints as well as production-line silicon solder bonds (die bonded headers) have been detected using the transmission-mode of operation of the microscope. Acoustic velocity of epoxy in an organic adhesive bond has also been measured using a combination of transmission and interference-mode of operation.
Tsai, C. S.; Wang, S. K.; and Lee, C. C., "Acoustic Imaging of Joined Surfaces" (1978). Proceedings of the ARPA/AFML Review of Progress in Quantitative NDE, September 1976–June 1977. 20.