Yoshiro Goto

Quantitative Voltage Measurement By A Software Closed Loop Technique In Electron Beam Testing

A software closed loop technique was devised for quantitative voltage measurement in electron beam testing for LSIs. A retarding voltage of an energy analyzer is controlled iteratively by a computer to reduce difference between a slice level and a secondary electron signal to zero. The voltage is determined by the retarding voltage at the cross point of the slice level and the energy distribution curve. Using this technique, the waveform of 256 sampling phases with more than 5 V amplitude can be measured in about 30 s with 200 mV voltage resolution and 100 ps time resolution.

Electron Beam (EB) delay tester

Abstract We have developed an EB delay tester for high-speed, high-accuracy measurement of the delay time between I/O pins of LSIs. In order to replace the measured LSI in the air, the LSI is placed on a multilayer board and measurement terminals on the back of the board are put in vacuum. For high-speed and high-accuracy measurement, we made an EB column with a large EB current of 100 nA and designed measuring technique based on binary search and feedback. The parameters of all measurement terminals are registered in advance to compensate position-dependence of the s-curve. Because these parameters are affected by EB current and vary over time, they are calibrated just before the edge timing measurement. Its measuring time is 168 ms and measurement accuracy is 56 ps when specified time resolution is 50 ps and repetition rate is 2.5 MHz.

Optical delay tester

The authors have developed an optical delay tester based on electro-optic sampling, and designed a prototype to test the timing of high-speed IC chips. The device puts an electro-optic crystal in contact with the terminals to be tested and measures the voltage waveform applied to the crystal. Measurement precision is 100 mV or better and timing precision measurement is 50 ps.

Hologram Writer Using a Plasma Display Panel

A hologram writer for a read-only page-oriented hologram memory has been developed. Data masks are produced by photographing dot patterns of a plasma display panel on a long-size film. A data pattern is obtained by covering a fixed bit mask with each data mask and stored in a small hologram. A hologram memory plate with total capacity of 2 x 10(7) bits was prepared by this hologram writer. This paper describes the construction and features of this hologram writer, as well as the characteristics of the hologram memory plate produced on a trial basis.

New Logic State Measurement Technique For The Electron Beam Tester

A multi-stroboscopic sampling (MSS) technique was devised for logic state measurement with the electron beam tester. Electron beam pulses are shot and secondary electron signals are sampled m times each repetition period of LSI operation. In addition, an interpolated s-curve (IPS) method was introduced in the MSS technique for quantitative voltage measurement. Using this technique, the measurement time required for 1024 logic states was reduced by 1/70 compared to the stroboscopic waveform measurement technique.