Failure Analysis: EOFM and EOP
Hi my dear photons! Long time no see! It's me, Fred Femto Field!
I was spending my holidays in the Quantic world! Passed the New Year's Eve over there, it was gorgeous!
Anyway, I'm back! And I was in the mood to continue our Failure Analysis Series... Today it's about EOFM and EOP!
In a DUT (Device Under Test) showing timing fails or propagation delay issues, can be quite challenging to do fault localization using traditional techniques like Emission Microscopy (EMMI) or Optical Beam Induced Resistance Change (OBIRCH). Therefore, a technique which provides more dynamic information is necessary for rapid block localization to minimize the amount of probing required. By that, Electro Optical Frequency Mapping (EOFM) and Electro Optical Probing (EOP) could measure the transistors switching and visualize it as an image by operating the transistors at specific frequency which could possibly be observed in the circuit.
EOP/EOFM techniques are laser based optical tools that do not contact the device directly but are able to measure the electrical activity through the backside silicon surface. A 1340 nm infrared laser irradiates the active zone of the DUT and the main resulting effects are either absorption or refraction. The later varies with the voltage level. With the sensitive detection system, this signal can be extracted, and semi-quantitative voltage information can be caught.
EOP/EOFM system can observe the reflected light during a transistor’s switch, and measures the frequency at that moment. The EOFM picks up the intensity of the signal under a certain frequency and visualizes it as an image. And EOP will show a waveform, which could be used for switching signal investigation.
Figure's Source: Ref. 1
That's all for today! We aren't still at the end of this series! New posts coming soon!
Cheers from 10-15!!
If you didn't follow the last posts of the Failure Analysis Series, you can always check them here:
(For the ones who want to know more about the aim of the blog, you can always click here)
References:
1 - N. Jandee, D. Korbsrisaw, F. Paulino, “Integrating EOP/EOFM as a Complimentary
Localization Technique for Open Via/Contact”, In Proc. IEEE International Symposium on the Physical and Failure Analysis of Integrated Circuits (IPFA), 2018.
2 - H. Zhang, P. Tien, X. Qian, “Electro Optical Probing / Frequency Mapping
(EOP/EOFM) Application in Failure Isolation of Advanced Analogue Devices”, In Proc. IEEE 24th International Symposium on the Physical and Failure Analysis of Integrated Circuits (IPFA), 2017.
3 - C. He, H. Zhang, J. Song, P. Tien “Study and application on thermal EOP (Electro Optical Probing) /EOFM (Electro Optical Frequency Mapping) technique", In Proc. IEEE International Symposium on the Physical and Failure Analysis of Integrated Circuits (IPFA), 2018.