Testable on-chip capacity

US6424058B1 · kind B1 · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Roland Frech · Esslingen am Neckar, DE
• Erich Klink · Schenefeld, DE
• Jochen Supper · Herrenberg, DE

Key dates

• Filing date: Sep 28, 2000
• Grant date: Jul 23, 2002
• Expiry date: Jan 9, 2021

Classification

• Technology area (CPC G): Physics
• CPC primary: G01R31/27
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

The invention relates to a testable on-chip capacitor cell 10 including a decoupling capacitor (Ci) which can be disconnected from the power distribution network and discharged through a cell internal discharge circuit. An externally controllable switch (Si) connects in a first switching position the decoupling capacitor to the power supply system and disconnects in a second switching position the decoupling capacitor from the power supply system and connects it to a resistor (Ri) which is part of the discharge circuit. An off-chip control unit (16) is provided for toggling the switch with a frequency fT between its first and second position to perform a capacitor test operation. By a current measurement device the averaged power supply current demand of the decoupling capacitor is measured when switch (Si) is toggled. The actual capacity of the decoupling capacitor is determined as a function of the power supply voltage, of the switch toggling frequency (fT) and of the averaged power supply current measured. The invention also relates to a semiconductor chip containing a plurality of capacitors cells of the type described, and to a method for testing the power supply decoupling ca…