As semiconductor technology keeps scaling down, failure analysis and device characterizations become more and more challenging. Global fault isolation without detailed circuit information comprises the majority of foundry EFA cases. Certain suspected areas can be isolated, but further narrow-down of transistor and device performance is very important with regards to process monitoring and failure analysis. A nanoprobing methodology is widely applied in advanced failure analysis, especially during device level electrical characterization. It is useful to verify device performance and to prove the problematic structure electrically. But sometimes the EFA spot coverage is too big to do nanoprobing analysis. Then further narrow-down is quite critical to identify the suspected structure before nanoprobing is employed. That means there is a gap between global fault isolation and localized device analysis. Under these kinds of situation, PVC and AFP current image are offen options to identify the suspected structure, but they still have their limitation for many soft defect or marginal fails. As in this case, PVC and AFP current image failed to identify the defect in the spot range. To overcome the shortage of PVC and AFP current image analysis, laser was innovatively applied in our current image analysis in this paper. As is known to all, proper wavelength laser can induce the photovoltaic effect in the device. The photovoltaic effect induced photo current can bring with it some information of the device. If this kind of information was properly interpreted, it can give us some clue of the device performance.

As semiconductor technology keeps scaling down, failure analysis and device characterizations become more and more challenging. Global fault isolation without detailed circuit information comprises the majority of foundry EFA cases. Certain suspected areas can be isolated, but further narrow-down of transistor and device performance is very important with regards to process monitoring and failure analysis. A nanoprobing methodology is widely applied in advanced failure analysis, especially during device level electrical characterization. It is useful to verify device performance and to prove the problematic structure electrically, especially for implantation related problems [1] [2]. Implantation related defects, or invisible defects, are the most challenging defect types for the application of fault isolation in all of the failure analysis jobs. The key challenge for these kinds of analyses is to make the defect visible. Sometimes, it is difficult or even impossible to visualize the defective point. Then, sufficient electrical evidence and theory analysis are important to bring the issue to resolution. For these kinds of analyses, a nanoprobing system is a necessary tool to conduct the detailed analysis. Combined with the device physics and electrical theory analysis, nanoprobing can bring out the perfect failure mechanism and problematic process step. There are two popular nanoprobing systems in our lab, one is SEM based and the other is AFM based. Both systems have their advantages and disadvantages in the electrical characterization and fault isolation field. In this paper, an implantation related issue was analyzed. Gross leakage was observed on the failed units as compared with good units. Global fault isolation, TIVA and EMMI failed to find the exclusive hotspot. With the GDS and process analysis, the nanoprobing was employed to the performance check on some of the suspected structures. Finally, the defective location was successfully isolated by nanoprobing. Combined with device physics and electrical analysis, the problematic process was successfully isolated.

This paper explains how the authors used nanoprobing techniques and electrical characterization to trace a die failure to a problem with the photoresist used to mask the wafer for ion implantation. Nanoprobing and leakage current measurements revealed significant differences between the inner and outer fingers of a multi-finger native transistor. Based on simulations, the differences can be attributed to severe scattering at the active edge of the Pwell due to problems with the photoresist, resulting in nonuniform doping profiles and die failure.

This paper describes the debug and analysis process of a challenging case study from wafer foundry which involved a circular patch functional leakage failure that was induced from device parametric drift due to thicker gate oxide with no detection signal from inline monitoring vehicles. It highlights the need for failure analyst to always be inquisitive and to deep dive into the failure symptoms to value-add the fab in discovering the root cause of the failure in challenging situation where information is limited.

The case study in this paper describes how collaboration between customer design and test teams and a thorough FAB investigation triggered by a detailed electrical analysis using the Atomic Force Nanoprober (AFP) resulted in the effective resolution of a challenging implant related issue on LDMOS structure that caused yield loss. The quick success in this case has led to a shorter yield ramp cycle on this new product for mass production.

This paper describes the observation of photoemissions from saturated transistors along a connecting path with open defect in the logic array. By exploiting this characteristic phenomenon to distinguish open related issues, we described with 2 case studies using Photon Emission Microscopy, CAD navigation and layout tracing to identify the ‘open’ failure path. Further layout and EBAC analysis are then employed to effectively localize the failure site.