New method of measuring the permittivity of silicon wafer, with relevance to permittivity-based quality sensing

A new method of measuring the permittivity of silicon wafers is provided. It removes the previously reported dependence of the measured permittivity on the silicon resistivity and on the electrode quality. Metal -semiconductor contacts or thin-film electrodes are not required. The method innovatively uses N-segment (e. g., N = 7) sandwiching aluminum-foil electrodes adhered to both surfaces of the wafer using double-sided ad-hesive tape, which provides adhesion and resistance enhancement (for ensuring that the meter measures the capacitance correctly). By measuring the capacitance C for various values of the capacitor area A (as provided by different numbers of segments) and plotting 1/C vs. 1/A, the permittivity is obtained from the slope and the effect of the electrode-specimen interface capacitance is removed. The relative permittivity (12) equals the conventionally obtained values. By using a sufficiently high value of N, the permittivity spatial distribution can be probed, thus enabling spatially resolved permittivity-based quality sensing.

Automated summary

A new method of measuring the permittivity of silicon wafers is introduced to eliminate the dependence on silicon resistivity and electrode quality. By using N-segment aluminum-foil electrodes attached to both surfaces of the wafer, the permittivity can be obtained and the effect of electrode-specimen interface capacitance can be removed. The method allows for spatially resolved permittivity-based quality sensing.