Waveform mapping and gated laser voltage imaging

Abstract

Systems, methods, and computer readable media to improve integrated circuit (IC) debug operations are described. In general, techniques are disclosed for acquiring/recording waveforms across an under-test IC during a single sweep of a laser scanning microscope (LSM). More particularly, techniques disclosed herein permit the acquisition of an integrated circuit's response to a test signal at each location across the IC in real-time. In practice the test signal consists of a stimulus portion that repeats after a given period. In one embodiment, the IC's response to multiple complete stimulus portions may be averaged and digitized. In another embodiment, the IC's response to multiple partial stimulus portions may be averaged and digitized. As used herein, the former approach is referred to aswaveform mapping, the latter as gated-LVI.

Description

[0001] priority claim [0002] This application claims U.S. Provisional Patent Application Serial No. 62 / 252,345, entitled "System and Method for Waveform Mapping and System and Method for Gated Laser Voltage Imaging (Gated-LVI)," filed November 5, 2015 and incorporated herein by reference priority. Background technique [0003] The present disclosure relates generally to the field of semiconductor diagnostics. More specifically, but in no way by way of limitation, the present disclosure relates to devices, systems, and methods for probing integrated circuits using laser illumination. [0004] When incident laser light is focused onto an integrated circuit (IC), device under test (DUT), free carriers within the device absorb and refract the photons supplied by the laser. As a result, the amplitude modulation of the reflected laser light corresponds to the DUT's response to the applied electrical test pattern. Analysis of reflected laser light reveals direct information abou...

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