An argon ion laser and an ir microscope have been combined to function as a unique combination for non- destructively testing the quality of bonded connections in microcircuits of the beam lead type. A microcircuit is heated with the focused beam from the laser and scanned with the microscope to determine the temperature pattern. Nonbonded microcircuits, poorly bonded microcircuits, and a multiplicity of adjacent poorly bonded leads have been detected by using this scanner. Preliminary results have indicated that a single nonbonded connection in an array of well bonded connections may be detected. An analytical check by computer analysis demonstrates the validity of the experimental data.
B. C. Miao and J. Longfellow, "A Laser-Assisted Infrared Scanning Technique for Evaluating Bonded Connections on Beam Lead Microcircuits," Appl. Opt. 9, 669-673 (1970)