Contactless measurement of local life of silicon chip - using oscillating circuit which is capacitively coupled with chip, and measuring surface conductivity and damping factor

摘要

The oscillating circuit is connected to an h. f generator supplying it. The chip area to be measured is capacitively coupled to the oscillating circuit, which it damps in accordance with its conductivity. The chip is illuminated by flashlights, and a voltmeter is connected to the oscillating circuit, whose resonance voltage is a measure for the crystal surface conductivity. Its variation in time is a measure of the chip area life. The oscillating circuit consists of a toroidal coil whose core is made of an UHF ferrite, on which a conducting metal strip is wound. Its one end is connected to a pin at a short distance from the chip, and the other to a chip supporting plate.