| 摘要 |
Modified scanning electron microscopes are usually employed for the implementation of methods for testing the electrical properties of printed circuit boards with the electron probe. As a consequence of the deflection, chromatic aberration and of the aberrations of the objective lens increasing greatly with the deflection angle, however, their scanning field is limited. In order to be able to test larger printed circuit boards without involved improvement of electron optics, it is proposed that the printed circuit board be subdivided into a plurality of adjoining regions, whereby the size of the regions respectively approximately corresponds to the size of the scanning field. Each of the networks lying only within one of the regions is then tested in a known manner. In order to detect shorts between networks of different regions as well as interruptions between contact points of networks extending beyond regions, the known testing method is followed by a further test cycle.
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