A Study Of Electro-optic Probing Technology With High Voltage Sensitivity And Ability Of Voltage Calibration

Currently, there have been a variety of techniques applying for the internalcharacteristics probing of the integrated circuit chip, among them, electro-opticalprobing technology has proven to be an IC non-intrusive dynamic probing technology.Due to a series of advantages of the electro-optical probing technology, it is a greatconcern subject in IC testing and microelectronics reliability research areas. Thisthesis is to study the high voltage sensitivity and voltage scaling calibrationtechnology for electro-optical probing, and have achieved certain results.Measuring electro-optic coefficient of the electro-optic materials for the study ofelectro-optical probing is particularly important. Therefore, the first research work ofelectro-optical probing technology research is to improve the simple reflex systemplatform, in order to measure electro-optic coefficient of the electro-optic materials. Inthe experiment, by improving the internal structure of the platform, theelectromagnetic shielding has come true, the simple reflection measurementfrequency bandwidth has achieved to the amplifier measurement limit frequency（10MHz）.With the development of integrated circuits, the device size is decreasing, thepower supply voltage is dropping, the signal voltage will be dropping, This requiresthe voltage sensitivity of the test equipment improved at the same time. This thesisfocuses on the voltage sensitivity of the electro-optical probing technology, in theexperiment, using the following four methods to increase the voltage sensitivity of theelectro-optical probing system. Respectively: the inverse piezoelectric effect induced、the inorganic materials with high electro-optic coefficient、the polymer materials withhigh electro-optic coefficient, the orientation effect of liquid polar molecules.The inverse piezoelectric effect induced: in the low-frequency diagnosis （0.1-100KHz）, we found a resonance peak near the10KHz when we research themodulation signal voltage produced by electro-optical material versus frequencycharacteristics, the signal induced by the resonance peak than the other frequencysignals improves two orders of magnitude. We can just take advantage of thisresonance peak, in the electro-optical probing, making the external frequencyadjustment to the resonance frequency of the electro-optic material, so that the use ofpiezoelectric resonance peak can increase the voltage sensitivity of two orders ofmagnitude.Inorganic materials with high electro-optic coefficient: in the electro-opticalprobing trials, more applications inorganic electro-optic crystal with the higherelectro-optic coefficient is LiNbO₃, the electro-optic coefficients γ13=8.6pm/V, γ33=30.8pm/V. Compared to the GaAs crystal, LiNbO₃crystal can greatly improve thevoltage sensitivity of the electro-optical probing system.Polymer materials with high electro-optic coefficient: Disperse Red1（DR1/SiO₂） hybrid thin film materials with high electro-optic coefficient used in theproduction of electro-optic probe, and its electro-optic coefficient can be as high as37pm/V, the electro-optical probing voltage sensitivity can be increased to1mV/Hz,and the organic material has a low dielectric constant, this can reduce the interferencewhen the circuit under test in the electro-optical measurement.The orientation effect of liquid polar molecules: the emanative electric field ofthe integrated circuit is only limited to within a few cubic microns of the circuitsurface in the free space. In order to fundamentally solve the problem of the air gap,we use the liquid membrane as electro-optic materials. Due to the liquid’s mobility,liquid film can contact with the surface of the circuit under test seamlessly. This canavoid air gaps effectively and improve the electro-optical conversion efficiency. Usingour electro-optical detection system for measuring electro-optic coefficient of DMFliquid film is95pm/V, and its voltage sensitivity improves two orders of magnitudethan GaAs material, greatly improved the voltage sensitivity of the system. In additionto the above advantages, compared to crystal growth and polishing of inorganic electro-optic crystal materials and high-temperature polarization of the polymerelectro-optic film, the production process of using liquid film for electro-opticalprobing is very simple, and the material is very rich.This thesis focuses on the voltage calibration of the electro-optical probingtechnology, we introduce the reference electrode on the probe surface for the first time.Without the introduction of the reference electrode, because the wiring distribution isdifferent, so the relationship between the amplitude of the electric field signal and theamplitude of its electro-optic signal induced is uncertainty; Due to the introduction ofthe reference electrode and the principle that the power line strive to shorten, as longas the thickness of the electro-optic crystal is less than the intervals of the wiredistribution, the power line is attracted by the reference electrode, and terminate thereference electrode. In contrast, the previous electro-optic signal is1/5of theintroduction of the reference electrode probe, so the introduction of the referenceelectrode probe greatly improve the voltage sensitivity of the system. This method isessential to the voltage calibration of the integrated circuit diagnosis.In the study of the voltage calibration problem, this paper proposed theintroduction of the signal with the frequency of the voltage signal on the referenceelectrode as the reference signal innovatively, and solve the problem of voltagecalibration; Measuring the electro-optical signal of the measured point, through theelectro-optical signal linear relationship with the measured signal, we can accuratelycalculate the amplitude of the signal electric field; Measuring the coplanar waveguidecircuit with the different wiring distribution, the experimental measurement error isless than6%, and meet the requirements of IC fault diagnosis.At the end of this thesis, we opened the IC, and measured the voltage signal ofthe IC internal transmission line. It made substantial progress for the prospects ofpractical applications of electro-optical probing technology in the IC test.