The Laser Voltage Imaging (LVI) technique, introduced in 2007 [1][2], has been demonstrated as a successful defect localization technique to address problems on advanced technologies. In this paper, several 28nm case studies are described on which the LVI technique and its derivatives provide a real added value to the defect localization part of the Failure Analysis flow. We will show that LVI images can be used as a great reference to improve the CAD alignment overlay accuracy which is critical for advanced technology debug. Then, we will introduce several case studies on 28nm technology on which Thermal Frequency Imaging (TFI) and Second Harmonic Detection (two LVI derivative techniques) allow efficient defect localization.

The Laser Voltage Imaging (LVI) technique [1], introduced in 2009, appears as a very promising approach for Failure Analysis application which allows mapping frequencies through the backside of integrated circuits. In this paper, we propose a new range of application based on the study of the LVI second harmonic for signal degradation analysis. After a theoretical study of the impact of signal degradation on the second harmonic, we will demonstrate the interest of this new approach on two case studies on ultimate technology (28nm). This technique is a new approach of failure analysis that maps timing degradation and duty cycle degradation. In order to confirm the degradations we will use the LVP Technique. The last part is two real case studies on which this LVI second harmonic technique was used to find the root cause of a 28nm process issue.

The bridge defect is one of the most difficult defects to locate. When classical static and dynamic optical techniques reach their limits, applying a dynamic signal on the power supplies for stimulating the defect allows obtaining useful additional information helping the localization. In this paper, we explore these techniques on a real case analysis of bridge defect in a scan chain on a 28nm technology node circuit. We will show that OBIRCH, LVI, static & dynamic EMMI do not give significant signatures for the defect localization. Finally we show that EMMI and LVI signatures applying a clock on the power supply bring relevant information to locate efficiently the defect.

For Very Deep submicron Technologies, techniques based on the analysis of reflected laser beam properties are widely used. The Laser Voltage Imaging (LVI) technique, introduced in 2009, allows mapping frequencies through the backside of integrated circuit. In this paper, we propose a new technique based on the LVI technique to debug a scan chain related issue. We describe the method to use LVI, usually dedicated to frequency mapping of digital active parts, in a way that enables localization of resistive leakage. Origin of this signal is investigated on a 40nm case study. This signal can be properly understood when two different effects, charge carrier density variations (LVI) and thermo reflectance effect (Thermal Frequency Imaging, TFI), are taken into account.

VLSI internal testing through silicon substrate has been widely studied and techniques like Time Resolved Emission has given impressive results. Nevertheless, Integrated Circuits (IC) are still evolving with more and more complex functions and various kinds of signals that could be split into two main categories: data and control. Controls activate specific block and according to the wide range of different blocks and device complexity, the first analysis task is to check block activity related to control line status. In this paper, we show how Time Resolved Imaging can precisely answer this challenge even in up-to-date technologies at low power supply.