International Business Machines Corporation

Dhruva J Acharyya

Kanak Behari Agarwal

Sani Richard Nassif

Rahul M Rao

Measurement of individual quiescent supply currents from multiple power supply pads located across a semiconductor die provides a means of characterizing across-die variation. A ratio is created by combining the individual pad supply current with the sum of all pad supply currents for a given die. An n-tuple is formed from the set of ratios for all pad supply currents to provide a unique signature for different across-die variation profiles.

Characterizing across-die process variation

A method and circuits for measuring operating and leakage current of individual blocks within an array of test circuit blocks provides measurement free of error due to leakage currents through non-selected circuit blocks, without requiring an independent test facility for each circuit block. The circuit includes a pair of power supply grids and selection circuits at each test circuit block to select between a test power grid and a 'rest' power grid used to supply current to the non-selected circuits. The leakage currents through the non-selected circuits are thus sourced from the rest grid and error that would otherwise be introduced in the test grid current measurement is avoided. The test circuit blocks may be ring oscillators, and the measured current may be the operating and/or leakage current of the ring oscillator. The circuit blocks may also include individual devices for IV (current-voltage) characterization using an additional gate input grid.

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Austin, TX, United States of America

Dhruva J Acharyya