Systems and method for laser voltage imaging
AssigneeDCG Systems, Inc.
InventorJames S. Vickers
Life of this patent
Estimating the term…
Abstract
An apparatus and method for laser voltage testing of a DUT is disclosed. The system enables laser voltage probing and laser voltage imaging of devices within the DUT. A selected area of the DUT is illuminating a while the DUT is receiving test signals causing certain of the active devices to modulate. Light reflected from the DUT is collected and is converted into an electrical signal. The electrical signal is sampled by an ADC and the output of the ADC is sent to an FPGA. The FPGA operates on the signal so as to provide an output that emulates a spectrum analyzer or a vector analyzer.
Claims23
A method for laser voltage testing of active devices within a device under test (DUT), comprising:
- illuminating a selected area of the DUT with laser beam while the DUT is receiving test signals causing certain of the active devices to switch states;
- collecting reflected light from the selected area;
- converting the reflected light into an electrical signal;
- sampling the electrical signal using an analog to digital (ADC) converter and thereby providing digital output;
- applying the digital output to a field programmable gate array (FPGA) and using the FPGA to perform operations on the digital output and thereby generate laser voltage testing signal corresponding to the switching states of the active devices within the selected area.
A system for laser voltage testing of active devices within a device under test (DUT), comprising:
- a mode locked laser (MLL) providing a train of laser pulses having pulse separation time oft nanoseconds;
- beam optics configured to direct the pulses onto selected area of the DUT and to collect reflected pulses from the DUT and direct the reflected pulses to a photosensor;
- a photosensor configured to receive the reflected pulses and output electrical signal corresponding to the reflected pulses, wherein the photosensor is configured to have relaxation time shorter than the pulse separation time oft nanoseconds;
- an analog to digital converter (ADC) electrically coupled to the photosensor and sampling the electrical signal of the photosensor in synchronization with the mode locked laser;
- a field programmable gate array (FPGA) electrically coupled to the ADC and configured to receive and operate on the sampling form the ADC and output a laser test signal corresponding to switching states of active devices within the selected area.
Dependencies are inferred from the claim text.