Transient IR imaging of light and flexible microelectronic devices

An advanced method for the quality assessment of microelectronic assemblies has been developed by combining IR thermography and several techniques for stimulation by transient temperature fields. The method exploits singularities in materials and interconnections by the observation of perturbations in transient heat flow phenomena. For very light microelectronic systems like chip-on-flex assemblies a method was developed taking advantage of short stimulations by photoflash. Such a method provided possibilities for detecting defects on the level of a single interconnection with a pitch of 80 μm. In addition, a programmable array of thermo-electric converters, prepared for the testing of a large variety of microelectronic assemblies, was also used to perform transient IR imaging for chip-on-flex assemblies.