Temperature control with a thermoelectric cooler (TEC) during laser decapsulation of plastic packages
Ablation was carried out on high voltage Schottky rectifiers at 25°C and −5°C (with a thermoelectric cooler or TEC), at 1.0 W and 3.9 W of laser power. In-situ measurement of the reverse current was conducted and correlated to the device junction temperature. It was found that the usage of a TEC increases the number of laser scans to reach the set current compliance of 100 µA after exposing the die, for ablation at 3.9 W, although eventual damage to the device is still unavoidable. The incorporation of a TEC below the sample is also demonstrated to be effective in reducing the device junction temperature during laser ablation.
Microelectronics failure analysis using laser ablation of composite materials in system in package
Fast and accurate decapsulation of integrated circuits packages is a key step of successful further observations and defect localization in microelectronics analysis laboratories. In addition to classical techniques, laser technology was introduced to enhance considerably performance in creating precise and local exposure of selective sub layers in complex system in package (SiP). In this paper, we will demonstrate all the benefits of this technique. The results of this new process were characterized according to laser parameters.
EFFECT OF SAMPLE PREPARATION ON WATER TREE RESISTANCE OF XLPE/SEBS BLENDS
The effects of an aromatic polymer, such as poly[styrene-b-(ethylene-co-butylene)b-styrene] (SEBS), and its preparation processes on water tree resistance, morphology, crystallinity, dielectric constant and dielectric loss tangent of crosslinked polyethylene (XLPE)/SEBS and XLPE/SEBS/ethylene vinyl acetate (EVA) blends were investigated. The XLPE/SEBS samples were characterized by means of differential scanning calorimetry, scanning electron microscopy, dielectric spectral analysis and the accelerated water treeing experiment. The results clearly showed that although SEBS was partially compatible with LDPE and it was dispersed evenly in XLPE matrix, the blends demonstrated excellent dielectric performances, such as dielectric constant and dissipation factor. The crystallinity of XLPE/SEBS blends was decreased with increase in SEBS content and it was further decreased with the addition of EVA. SEBS could effectively improve the water-tree resistance of XLPE and both SEBS and EVA were found to improve the water tree resistance of XLPE synergistically as expected. The differences in sample preparation processes could change the phase morphology and dielectric performance of the blends, and could also influence the dispersion of SEBS in XLPE matrix as well as the crystallinity of the blends. Different preparation processes led to different water tree resistance behaviours of the samples. The improvement of SEBS dispersion in XLPE matrix helped to improve the water tree resistance of XLPE.