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Abstract: In FA laboratories a significant number of photon emission microscopy (PEM) systems are equipped with the most common detector, namely cooled Si-CCD camera. Backside reflected light microscopy (RLM) and photon emission microscopy (PEM) using this detector are possible but strongly limited by the interaction of light with silicon substrate. In this work, we show the improvement of the RLM and PEM performed from the chip backside using standard cooled Si-CCD camera by localized focused-ion-beam (FIB) assisted silicon substrate removal. Thinning down the silicon substrate significantly improves signal-to-noise ratio of the techniques as well as their resolving properties. It also enables extended spectral analysis, also in the visible regime of the light spectrum. This study has been done using 120nm technology process test structures. [Copyright &y& Elsevier]

Abstract: Failure analysis techniques had been proved to be efficient to localize defects allowing root cause analysis and corrective actions at design or manufacturing level. Unfortunately, end user’s component expertise laboratories have very rarely access to the device design (CAD) they are analysing and characterizing. Electronics components come like a black box so they have to find out the information by other means to be able to link an abnormal electronic behaviour to a specific internal structure. We have proven that Laser Stimulation (LS) is a valuable technique to overcome this issue. These techniques allow a very good correlation regarding the sensitive sites on the device and the electrical functions performed. We have embedded these techniques in a specific test flow to perform CADless accurate device failure analysis and characterization of margin evolutions in operating parameters for reliability study purposes. [Copyright &y& Elsevier]

Abstract: A large range of commercial deep submicron VLSI devices are used for avionic designs. Due to the scaling down, an ever higher level of integration and the use of new materials in foundries, the main failure mechanisms are changing while new ones appear. Lifetimes related to these failure mechanisms are suspected of being shorter and shorter so failure rate prediction becomes a great challenge for deep submicron (DSM) semiconductor reliability. We propose in this paper, a new approach based on technologies analysis in order to determine potential reliability risks regarding the specific use of DSM components for avionic applications. [Copyright &y& Elsevier]

Abstract: Dynamic laser stimulation (DLS) techniques have been introduced over the past few years to tackle the localization of dynamic failures. This article first reviews the principles behind DLS techniques and their implementation based on monitoring functional test mapping (pass/fail) signals and monitoring other electrical variations. The integration of DLS within a dynamic optical analysis workflow in failure analysis and design debug is then presented. Finally improvements aimed at increasing the ability of DLS techniques to solve ever-growing range of subtle soft defects issues are discussed. [Copyright &y& Elsevier]

Abstract: The retention, reliability and security of data stored in Non Volatile Memories (NVM) are problems of utmost importance for the microelectronics industry. All these issues could be addressed by physically reading the memory content. A method to deduce memory organization and then to read data in Flash-EEPROM devices is presented. It is based on failure analysis techniques such as Focused Ion Beam (FIB), Scanning Kelvin Probe Microscopy (SKPM) and Scanning Capacitance Microscopy (SCM). An application is demonstrated on the Flash memory of a Programmable Integrated Circuit (PIC) from Microchip dedicated to smart card applications. [Copyright &y& Elsevier]

Abstract: A method to measure “on site” programmed charges in EEPROM devices is presented. Electrical AFM based techniques (Electric Force Microscopy (EFM) and Scanning Kelvin Probe Microscopy (SKPM)) are used to probe directly floating gate potentials. Both preparation and probing methods are discussed. Sample preparation to access floating gate/oxide interfaces at a few nanometers distance without discharging the data reveals to be the key point, more than the probing technique itself. [Copyright &y& Elsevier]

Optical analysis techniques are key tools for the failure analysis and defect localization in integrated circuits. Using a confocal laser microscope, it is possible to extract different pieces of information such as spatial distribution of signals or voltage waveforms. Blur is getting a more and critical issue as technology pitch is getting smaller, very close to resolution limits. Find the correct focus, is a recurrent problem to solve in optical microscopy. The expert has to correct the blur disrupting the image, by manually searching the good focus. By consequences, this step may take a long time to identify regions of interest in the circuit. With this purpose in mind, the aim of this paper, is to propose an automatic process estimating the out-of-focus blur parameters characterized by specific attributes. Proposed technique takes advantage of extracted features in the Discrete Cosine Transform (DCT) of blurred images. The blur information is identified and allows to recover the blur's kernel. Finally, the accuracy and the robustness of the suggested process is demonstrated on real blurred images. [ABSTRACT FROM AUTHOR]

Previous study on the invasiveness of the CW 1340 nm laser source used in failure analysis, pinpointed silicide diffusions issue and experimentally defined a safe experimental area. Nevertheless, experimentally defining a safe area is a very long process. So we bypassed it by a new approach based on thermal laser stress modelling for defect localization applications (LVI/OBIRCH, cw-LVP). The first target of this study is the 28 nm FDSOI technologies. The results of this simulation are also compared to experiments to check accordance with the temperatures of material diffusion. The model can be used to define safe and not safe areas of interaction between the laser and the IC (exposure time, laser power). Laser invasiveness issues for different technologies and geometries can also be addressed. [ABSTRACT FROM AUTHOR]

Electro optical techniques (EOP: electro optical probing and EOFM: electro optical frequency mapping) are effective backside contactless methods for defect localization and design debug for VLSI. The image mode (EOFM) gives only one frequency at each scan. In this case, the frequency mapping is a long and hard task. Furthermore, temporal information is not included in EOFM mode. Building a map by point by point EOP is usually too long so it cannot be used as it is to extract all the frequencies of interest in a region of interest. To overcome this limitation, we have developed an automatic process using EOP mode with a wavelets approach and autocorrelation. Temporal and frequency information are simultaneously computed with only one acquisition. We will underline the challenge and define application boundaries of this technique. [ABSTRACT FROM AUTHOR]

A newly integrated pulsed laser system has been utilized to investigate the effects of voltage stress on single event upset (SEU) of flip flop chain manufactured in 65 nm bulk CMOS technology. Laser mappings of the flip flop chain revealed that the SEU sensitive regions increased with laser energy. Post-processing of the data from the laser mapping facilitated the plotting of the cross-section versus laser energy curve. We found a clear shift in the cross-section curves after voltage stress of 130 h. Comparisons of data revealed at least a doubled increase in sensitive areas after voltage stress. During the voltage stress, various electrical parameters were monitored and changes were observed. It was found that the increase in SEU sensitivity is related to electrical parameter changes and SPICE simulation results concur likewise. [ABSTRACT FROM AUTHOR]

This paper describes a new way to analyze inertial MEMS with the electro-optical technique. Usually, this technique is used in failure analysis to probe on electronic devices from old technologies to modern VLSI. In our case, we make use of the variation in power of the reflected beam between different layers of materials in an accelerometer (MEMS). We introduce a new method based on the electro-optical technique to extract a physical resonant frequency in inertial MEMS. [ABSTRACT FROM AUTHOR]

Dynamic photon emission is an efficient tool for timing analysis of various areas. However, advances in transistors integration bring more complex test patterns and more objects to investigate. As a consequence, understanding the analyzed area and finding nodes of interest can be difficult. In this paper, a method for drawing synthesis of the various signals met inside an area is reported. It is based on unsupervised learning tool for dimension reduction and clustering. The process is applied to real data to show its efficiency and its quality is evaluated. [ABSTRACT FROM AUTHOR]

Electro Optical Probing (EOP) technique is an efficient backside contactless technique to measure waveforms in modern VLSI circuits. The signal related intensity variation of the reflected beam is very weak therefore, to acquire a signal with enough Signal to Noise Ratio, averaging techniques are usually performed. Resulting acquisition time for one waveform is too long to implement point to point probing to image mode. To overcome this limitation, we have developed a new filtering by wavelets approach to keep a good SNR while significantly reducing this acquisition time. It opens the doors to new multipoint probing applications. In this paper, we describe the technique, its efficiency in terms of SNR, execution time and limits. [ABSTRACT FROM AUTHOR]

In addition to Emission Microscopy, Electro-Optical Probing (EOP) technique has shown its efficiency in the world of failure analysis since the last decades and its ability to measure waveforms on various devices. The different physical parameters that affect and modify the reflected laser probing beam through active silicon components are just beginning to be well known. All the physical and environmental parameters contribute to the modulation of the reflected laser probing beam onto structures under test. However, the origins of EOP signals from bipolar transistors junctions used in a lot of analog devices are not well known and not that much described in the literature. In this paper we present backside EOP signal measurements from bipolar devices. We compare these measurements on a failed transistor and on a reference transistor and we interpret the results according to a model previously developed for silicon devices (MOS and Bipolar). [ABSTRACT FROM AUTHOR]

Most optical defect localization techniques such as dynamic laser stimulation or photon emission microscopy require a pattern image of the device to be taken. The main purpose is for device navigation, but it also enables the analyst to identify the location of the monitored activity by superimposing it onto the pattern image. The defect localization workflow usually starts at low or medium magnification. At these scales, several factors can lead to a lack of orthogonality of the sample with the optical axis of the system. Therefore, images can be locally out of focus and poorly resolved. In this paper, a method based on Depth of Field Extension is suggested to correct the pattern image. [ABSTRACT FROM AUTHOR]

Highlights: [•] Frequency of emission is automatically determined. [•] It is based on a combination of CWT and autocorrelation. [•] Test structure is a FPGA in which 3 inverter chains are implemented. [•] Three different frequency sets are used for stimulation. [•] Maximum detection rates are 97% et 100 % for design01/03. A most 65% on design02. [Copyright &y& Elsevier]

Highlights: [•] We demonstrate the impact of NBTI on the Single-Event Upset threshold of a 65nm SRAM cell. [•] The SEU threshold measured by laser testing decreases over time after NBTI accelerated stress. [•] On the tested device, this effect seems to be a concern only for long-term space missions. [Copyright &y& Elsevier]

Abstract: Thermal laser stimulation on sub-Micronics interconnection structures is well known. The usual approach is to consider them as a resistor, whatever the structure is. We experimentally showed the weaknesses of this assumption which has to be reconsidered. In this paper we develop a new analytical model based on fine characterization of the dynamic behavior structure heated and cooled. In addition to a better understanding of thermal laser stimulation signature, this modelization opens a wide range of application: structure identification, 3-D localization, etc. It should be a key for failure analysis accuracy and efficiency on Back End Of the Line test structures. [Copyright &y& Elsevier]

Abstract: The study is carried out on AlGaN/GaN HEMTs presenting current collapse effect at V ds lower than 6V. This effect is completely recovered by illuminating the component with light of 710nm wavelength (1.75eV). The spectral analysis of the light emission in the visible near infrared spectrum shows a bell-shape with superimposed distinct emission peaks. These features suggest that the electroluminescence (EL) signal is due to the direct intraband of electrons and inelastic intraband transition of electrons due to scattering by charged centres. Photoionisation experiments have been conducted to determine the light wavelengths/energies that separately change the drain current and the gate leakage current. [Copyright &y& Elsevier]

Abstract: Dynamic laser stimulation (DLS) techniques based on operating integrated circuits (ICs) become a standard failure analysis technique for soft defect localization. This type of defect is getting more and more common with advanced technology; therefore, DLS is becoming a key technique for defect localization. To perform this technique, the determination of a pass–fail border in shmoo plot is necessary. It is essential to know the impact of the defect on the shmoo plot shape with different defects. This paper presents shmoos plots simulation for common defects encountered in ICs failure analysis. Ability of DLS to detect defects according to their resistances and capacitances values are clearly established. In the second part of this paper, case studies which validate simulations results are presented. [Copyright &y& Elsevier]

Abstract: This paper presents a new method of passivation control by electroluminescence (EL) in 0.15μm AlGaN/GaN HEMT. The electroluminescence signature in one finger HEMTs (W =1×100μm), and eight fingers ones (W =8×125μm), is modified by defects located at the passivation/semiconductor interface and is characterized by a light emission along the drain contact. This abnormal emission reveals some modification of the electric field distribution in the gate-drain space probably induced by traps located at the passivation/semiconductor interface. These traps contribute to the creation of a virtual gate in the gate-drain space. [Copyright &y& Elsevier]

Abstract: We present in this study the effect of electrical ageing on silicon (Si) NPN bipolar transistors. This study is based on a sample of half-hundred components, which have been fabricated in the early 1980s, which represents an exceptional experience feedback. By means of static and low frequency noise measurements, which are used as diagnostic tools for reliability assessment, we have noticed a good accordance with a physical model based on an oxide charge modulation. We have also used emission microscopy and electron beam-induced current analysis in order to visualize and to localize the defects in the structure. These have been located in the spacer oxide at the periphery of the base-emitter junction. [Copyright &y& Elsevier]

Abstract: Various optical defect localization techniques are applied on the same integrated circuits (IC). These circuits were previously stressed by Electro Static Discharges (ESD) to create defects. The results obtained by each technique were analyzed to determine the nature of the defects. The different data are compared to assess their sensitivity and to evaluate the contribution of each technique in a failure analysis flow. [Copyright &y& Elsevier]

Abstract: This paper presents an improvement of the time resolution of the Photoelectric Laser Stimulation technique using the phase of a mode-locked laser as a reference to generate an electrical stimulus for the device under test. This synchronization system was applied to observe signal propagation in an 860 MHz ring oscillator. [Copyright &y& Elsevier]

Device simulations of laser induced SEU in an SRAM cell are performed with pulse durations from 100 fs to 100 μs. SEU threshold energy is notably dependent on the pulse duration. Two regimes are identified and modeled analytically and electrically. [ABSTRACT FROM AUTHOR]

Abstract: We report on the degradation of platinum micro-heating elements operating at high temperatures. Devices with platinum heaters suspended on micro-machined dielectric membranes were self-heated at high temperature until failure. Optical and SEM observations combined with mechanical deformation measurements and Thermal Laser Stimulation techniques were used to analyze the failure mechanisms of the micro-heating elements. Platinum atoms migration and breaking of the membrane were two failure modes observed. At high temperature, the migration of the platinum atoms was linked to the mechanical stress in the dielectric membrane. The Thermal Laser Stimulation technique revealed the formation of vertical as well as lateral thermocouples at mechanically deformed areas. One explanation proposed is that those thermocouples are the result of Si diffusion from the Si3N4 membrane into the platinum heater as well as electro-stress migration of platinum atoms. [Copyright &y& Elsevier]

Abstract: Dynamic Laser Stimulation (DLS) techniques based on near-infrared laser scanning are used for failure analysis, design debug, and time margin studies or critical path analysis. In failure analysis, it is applied to localize defects when static techniques can not be applied. Moving from static to dynamic laser stimulation requires a more complex electrical setup. This paper presents several DLS case studies along with the used DLS setup. It is shown that design-process related issues as well as physical defects such as resistive contacts are rapidly and precisely localized. [Copyright &y& Elsevier]

Abstract: Light emission is routinely used to locate abnormal areas in failed ICs. Localization is done while the device is activated by a test pattern in a loop. Time Resolved Emission (TRE) has the potential to analyse faults by studying the emission of one area as a function of time. For failure analysis both techniques are valuable to identify where and when abnormal emission events have occurred. At low VDD, using only one or the other emission technique has shown some limitations. A solution, presented here, is to add a NIR PMT detector on an existing light emission microscope. Choice of detectors, performances and implementation are detailed on 120 and 90 nm structures. [Copyright &y& Elsevier]

Abstract: In failure analysis laboratory, infrared laser stimulation techniques are more and more used for performing accurate defect localization on IC surface. Signatures obtained on metallic elements are well known, but weak data are available on signatures of semiconductors elements. Our investigations consist of studying impact of semiconductors materials on IR Laser Stimulation signal during a failure analysis. Frontside and backside Thermal Laser Stimulation (TLS) experiments were performed on n+/p+ diffusion and polycrystalline resistors from 0.18μm technology, both silicided (CoSi2) and unsilicided. Experimental results are presented and discussed for different W/L ratios. The impact of different semiconductors materials on TLS measurements is discussed and verified by experiment. [Copyright &y& Elsevier]

Abstract: Dynamic Laser Stimulation (DLS) is an important technique for IC analysis and timing characterization. Implementations and practical considerations are presented for SDL, RIL and LADA techniques as well as the latest methodology know as Delay Variation Mapping (DVM). Downside of dynamic laser techniques is higher complexity of IC setup and results interpretation. Understanding these aspects is necessary to benefit from DLS for the IC analysis and timing characterization. [Copyright &y& Elsevier]

Abstract: The failure signatures of a grounded-base NPN bipolar ESD protection under multiple TLP and HBM stresses are analyzed. For this particular device having a graded collector region, multiple TLP or HBM stresses result in different types of defects. OBIC techniques and TCAD simulations are used to thoroughly analyze the involved physical mechanisms. [Copyright &y& Elsevier]

This paper presents an experimental comparison of laser beam based techniques applied to a case study concerning ESD defect location. Thermal laser stimulation and non-biased optical beam induced current techniques are evaluated and discussed. Experimental results demonstrate the advantages and weak points of the two approaches. [Copyright &y& Elsevier]

The number of circuit design iterations due to electrostatic discharge (ESD) failures increases with the complexity of VLSI technologies and their shrinking. In this paper, we show how TCAD and ESD SPICE modeling can be used to solve ESD protection issues in an analog CMOS technology. [Copyright &y& Elsevier]