Conference Paper

Space charge measurement of PCB insulations at various temperatures

Fuji Electric Co., Edo, Tōkyō, Japan
DOI: 10.1109/ICSD.2004.1350318 Conference: Solid Dielectrics, 2004. ICSD 2004. Proceedings of the 2004 IEEE International Conference on, Volume: 1
Source: IEEE Xplore


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.

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    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.
    Solid Dielectrics, 2007. ICSD '07. IEEE International Conference on; 08/2007
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    ABSTRACT: More and more electronics are to be used under various adverse environments at high temperatures with high humidity. Spatial distributions of internal charge carriers mainly due to ionic impurities that appear in hot and humid environments are considered to affect the reliability of bulk insulation. Therefore, the authors examined space charge behavior inside paper/phenol-resin composites for printed circuit boards under dc voltages, focusing on the effect of water absorption temperature. Both the sample weight and thickness are increased monotonically by the immersion in water with an increase in water temperature from 24°C to 85°C, indicating that the water absorption by the sample is temperature dependent. In early periods of water absorption up to 10 hours, the electric field decreases near the two electrodes and increases in the other regions. Furthermore, heterocharge formation is observed near the cathode as the water absorption progresses, which becomes more significant at higher water temperatures. Ion chromatography analyses detected a lot of ions such as Na+, NH4+ and Cl- from the water, in which the sample had been immersed for 100 hours at various temperatures. It is highly possible that these ions are responsible for the heterocharge formation.
    IEEJ Transactions on Fundamentals and Materials 01/2008; 128(9):585-590. DOI:10.1541/ieejfms.128.585