| This paper introduced common methods of micro-resistance test. We choose the four-probe method to study after comparing the merits of each method. The basic principle, measured quasi-conditions, current selection, edge and thickness of the amendment, the choice of measurement region of conventional linear four-probe method was analyzed. Started with the conventional linear four-probe method, the improved Vanderbilt law was introduced, which is also called oblique four-probe method. The measurement principle and test conditions were described, which is better than conventional linear four-probe method. Then the principle of Rymaszewski oblique style square four-probe method for sheet resistivity test was discussed, and the resistivity distribution of 4-inch silicon wafers was determined using this method.The division number and difference of the resistivity was identified and the appropriate threshold was selected from the statistical distribution of resistivity. The resistivity data were attributed to different fuzzy sets according to the fuzzy mathematics theory, the same fuzzy sets corresponding to same resistivity, so the resistance can make the intervals distribution, at last, mapping graph was formed by resistivity graphics drawn with MaTlab software. The express methods selected for mapping diagram are: radial diagram, radial comparison chart, color pictures, gray scale and contour map. Gray scale method, which is determined as the best characterization of sheet resistance for mapping graph by comparing the representation of different sheet resistance graph, was choosen to express the samples test results. The purpose of characterized sheet resistance mapping graph study is to make it clear of the sheet resistance distribution, and increase the analysis effect of test results. This research was intended to improve the representations of the results using original prototype, after the improvement, the representation of results is more intuitive and specific. |
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