An integrated CMOS-MEMS probe having two-tips per cantilever for individual contact sensing and kelvin measurement with two cantilevers

The MEMS-made probe cards can drastically improve semiconductor wafer test quality as compared to traditional tungsten probe. To further take advantage of MEMS technology, the authors propose a CMOS-MEMS integrated probe card, to solve the tradeoff problem of measurement precision and excess pad damage by skating, by 4-terminal (Kelvin) measurement with two-tracks-per-cantilever needle. Putting two tips on each cantilever enables us to detect electrical contact and to decrease skating. And by this structure, electrical properties of a device under test are measured precisely with 4-terminal measurement which can eliminate track resistance and contact resistance. We measured the resistance of a gold thin film. With 2-terminal method, the resistance was measured to be about 74 ohms. However with Kelvin measurement, the resistance was 0.012-0.022 ohms. This result shows the successful implementation of 4-terminal measurement probe with MEMS technology.