## Failure Analysis: EOFM and EOP ## ### Hi my dear photons! Long time no see! It's me, **[Fred Femto Field](https://steemit.com/introduceyourself/@heteronimo/the-first-heteronym)**! 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. <center>!(https://cdn.steemitimages.com/DQmeteCsocGcu8gByTnFi8Eo6R6BW53SoN3GDN63PqudoBh/image.png)</center> ###### <center> Figure's Source: Ref. 1 </center> ###### ## That's all for today! We aren't still at the end of this series! New posts coming soon! Cheers from **10<sup>-15</sup>**!! <center>***If you didn't follow the last posts of the Failure Analysis Series, you can always check them here:***</center> - **[Part 1: Dissecting EMMI and OBIRCH](https://steemit.com/science/@heteronimo/failure-analysis-with-fred-femto-field-part-1)** - **[Part 2: Something about DALS](https://steemit.com/steemstem/@heteronimo/failure-analysis-with-fred-femto-field-part-2)** - **[Part 3: Surfing on an Infra-Red Wave](https://steemit.com/steemstem/@heteronimo/failure-analysis-with-fred-femto-field-part-3)** <center>***(For the ones who want to know more about the aim of the blog, you can always click [here](https://steemit.com/lifestyle/@heteronimo/about-heteronysm))***</center> **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.