Space charge measurement of PCB insulations at various temperatures

Conference Paper · August 2004with5 Reads
DOI: 10.1109/ICSD.2004.1350318 · Source: IEEE Xplore
Conference: Solid Dielectrics, 2004. ICSD 2004. Proceedings of the 2004 IEEE International Conference on, Volume: 1
Abstract
Space charge profiles of printed circuit boards used in the telecommunication industry were observed under dc electric fields with increasing temperature. Hetero charge distributions were formed in specimens made of aramid paper and epoxy resin, and the electric field near each electrode was enhanced. The results also suggest that the internal charge profile depends on the treatment of aramid papers.
  • [Show abstract] [Hide abstract] ABSTRACT: While the reliability of bulk insulation has become important particularly in multilayer boards and embedded boards, electronics are to be used under various environments such as at high temperature and in high humidity. We observed internal space charge behavior for two types of epoxy composites under dc electric fields to investigate the influence of water at high temperature. In the case of glass/epoxy specimen, homocharge is observed at water-treated specimen, and spatial oscillations become clearer in the water-treated specimens. Electric field in the vicinity of the electrodes shows the injection of homocharge. In aramid/epoxy specimens, heterocharge is observed at water-treated specimens, i.e. negative charge accumulates near the anode, while positive charge accumulates near the cathode. Electric field is enhanced just before each electrode. In order to further examine the mechanism of space charge formation, we have developed a new system that allows in situ space charge observation during ion migration tests at high temperature and high humidity. Using this in situ system, it was also confirmed that heterocharge was observed in water-treated aramid/epoxy composite.
    Conference Paper · Jul 2005 · IEEJ Transactions on Fundamentals and Materials
  • [Show abstract] [Hide abstract] ABSTRACT: The reliability of bulk insulation is particularly important in multilayered or embedded printed circuit boards (PCBs). Moreover, PCBs are mounted in quite a lot of devices, which are often used at high temperatures and in high humidity. We observed internal space charge behavior in two typical types of epoxy composites for PCBs, namely those with aramid and with glass, under dc voltage to investigate the effect of water temperature. It was observed that the space charge profiles showed spatial oscillation with 3 or 5 iterative units in agreement with the number of composite layers in samples. In the case of the aramid/epoxy composite, homocharge is formed near the two electrodes in the sample at 40 °C, while hetrocharge is accumulated at 85 °C. The ion-chromatography analysis showed that the contents of several kinds of cations were much higher especially in the aramid/epoxy composite treated in water at 85 °C than in the one treated at 40 °C. This indicates that the water treatment enhances dissociation of ions. In the case of the glass/epoxy composite, homocharge is formed near the electrodes in the sample under dc voltage if it was treated in water at 85 °C. Water seems to enhance the charge accumulation in both samples.
    Article · Jan 2006
  • [Show abstract] [Hide abstract] ABSTRACT: The properties of bulk insulation in printed circuit boards (PCBs) have become even more important, especially for those with a multilayered or embedded structure. In particular, the spatial distribution of internal charge carriers, mainly due to ionic impurities, is thought to affect the reliability of bulk insulation. Therefore, the effects of humidity and temperature on space charge distribution profiles in a five-layered composite of aramid paper and epoxy resin are studied in this paper. More charge carriers are induced at higher temperatures with humidity. A relative humidity of 55% is high enough to induce a saturated amount of charge carriers in the present samples at 40 °C.
    Conference Paper · Aug 2007
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