Multicriterial approach correlation of the solder joints functional tests results

The assembling of the electronic components on PCBs becomes a key issue in electronic packaging reliability. The solder joints resulting from the soldering process represent an important outcome for the PCB assembling. Moreover, the Lead-Free soldering requests, imposed by the RoHS Directive, can cause difficulties in obtaining a high quality/reliable soldering process. Considering the reliability of electronic modules as expression of solder joints functionality, could be emphasized the lack of tests over solder joints functionality on assembling line. Usually are realized optical inspections and, in precise situation, X-Ray analysis are done over assembled PCBs being followed by “in circuit” electrical functional tests. The defects type “hide” or “cold/dry joints” could be not found. In the paper are presented the results of the functional tests of solder joints realized in two soldering technology, infrared-convection and vapor phase. Regarding to thermal functionality, infrared analysis of temperature distribution on the surface of a populated PCBs using thermovision were done. A correlation among functionality, reliability and thermovision functional analysis will be realized based on the experiments results. In consequence, the authors emphasize thermovision as available in circuit indirect test method for “hide” defects of solder joints.