Measuring back-side voltage of an integrated circuit

Abstract

Methods for integrated circuit diagnosis, characterization or modification using a charged particle beam. In one implementation, the bulk silicon substrate of an integrated circuit is thinned to about 1 to 3 mum from the deepest well, a voltage is applied to a circuit element that is beneath the outer surface of the thinned substrate. The applied voltage induces an electrical potential on the outer surface, which is detected as a surface feature on the outer surface by its interaction with the charged particle beam.

Description

technical field [0001] The present invention relates to the use of charged particle beams for integrated circuit diagnosis, qualification and modification. Background technique [0002] Over the years, e-beam diagnostic systems have become powerful tools for integrated circuit (IC) qualification and debug applications. Notable aspects of electron beam diagnostic systems include secondary electron imaging, circuit navigation using embedded computer automation design (CAD) displays, and voltage measurement from active circuits using voltage contrast principles. (see eg US Patent No. 4706019). Electron beam diagnostic systems are traditionally used on the front side of integrated circuits. The implementation of face-down or flip-chip integrated circuit packaging imposes severe limitations on the use of e-beam diagnostic systems. Integrated circuits using flip-chip packaging have only the backside (silicon substrate) of the integrated circuit exposed. [0003] Three methods ...

AI Technical Summary

Problems solved by technology

This method requires the labor and expense of using specialized equipment to deliver the necessary chemicals

Once the substrate is completely removed, there is still the problem of locating exactly which nodes to probe

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