Frank Altmann

Fraunhofer Institute for Microstructure of Materials and Systems | IWM · Center for Applied Microstructure Diagnostics (CAM)

This work demonstrates the capability of E-beam probing, combined with optical techniques, to effectively monitor the activity of the IC structures and extract the signals from a 16nm technology device through the silicon backside. We conducted optical probing to localize the area of interest on the device, where we aimed the E-beam probing to gath...

Presentation slides for the ISTFA 2024 Tutorial session “Machine Learning in Semiconductor Failure Analysis: Techniques and Case Studies.”

In this paper, the failure analysis of InGaAs/GaAs-on-Si nanoridge laser diodes using the electron beam based nano-probing technique is presented. These III-V laser devices are fabricated using the nano-ridge engineering approach where the misfit dislocations generated during the growth of InGaAs/GaAs layers on silicon substrate are confined away f...

Non-destructive inspection and analysis techniques are crucial for quality assessment and defect analysis in various industries. They enable for screening and monitoring of parts and products without alteration or impact, facilitating the exploration of material interactions and defect formation. With increasing complexity in microelectronic techno...

Optical probing methods through the chip backside have been demonstrated to be powerful attack techniques in the field of electronic security. However, these attacks typically require specific circuit conditions, such as enforcing gate or register switching at certain frequencies or repeating measurements over multiple executions to achieve an acce...

This paper presents a root cause analysis case study of defective Hall effect sensor devices. The study identified a complex failure mode caused by chip–package interaction, which has a similar signature to discharging defects such as ESDFOS (electrostatic discharge from outside to surface). However, the study revealed that the defect was induced b...

The present work deals with the development of Co3O4-based catalysts for potential application in catalytic gas sensors for methane (CH4) detection. Among the transition-metal oxide catalysts, Co3O4 exhibits the highest activity in catalytic combustion. Doping Co3O4 with another metal can further improve its catalytic performance. Despite their pro...

The role of threading dislocations in the intrinsic degradation of lateral GaN devices during high reverse bias stress tests (RBSTs) is largely unknown. We now present the results on lateral p-GaN/AlGaN/2DEG heterojunctions with a width of 200 μm in GaN-on-Si. A time-dependent permanent degradation of the heterojunction under high reverse bias and...

Presentation slides for the ISTFA 2023 Tutorial session “Machine Learning Based Data and Signal Analysis Methods for the Application in Failure Analysis (2023 Update).”

Contactless probing methods through the chip backside have been demonstrated to be powerful attack techniques in the field of electronic security. However, these attacks typically require the adversary to run the circuit under specific conditions, such as enforcing the switching of gates or registers with certain frequencies or repeating measuremen...

Non-destructive inspection and analysis techniques are crucial for quality assessment and defect analysis in various industries. They enable for screening and monitoring of parts and products without alteration or impact, facilitating the exploration of material interactions and defect formation. With increasing complexity in microelectronic techno...

This paper presents a root cause analysis case study of defective Hall-effect sensor devices. The study identified a complex failure mode caused by chip-package interaction, which has a similar signature to discharging defects such as ESDFOS. However, the study revealed that the defect was induced by local mechanical force applied to IC structures...

Localizing security-relevant hard blocks on modern System-on-Chips (SoCs) for physical attacks, such as sidechannel analysis and fault attacks, has become increasingly time-consuming due to ever-increasing chip-area and - complexity. While this development increases the effort and reverse engineering cost, it is not sufficient to withstand resolute...

Presentation slides for the ISTFA 2023 Tutorial session “SEM Based EBIC, EBAC, and E-Beam Probing Techniques.”

Electronic Device Failure Analysis Technology Roadmap examines the trends shaping the future of semiconductor technology as well as the tools and techniques that will be required to detect, analyze, and remediate failures. The information is organized into ten chapters, seven of which assess the capabilities, limitations, and future needs of fault...

Electronic Device Failure Analysis Technology Roadmap examines the trends shaping the future of semiconductor technology as well as the tools and techniques that will be required to detect, analyze, and remediate failures. The information is organized into ten chapters, seven of which assess the capabilities, limitations, and future needs of fault...

It is shown that the operating temperature of pellistors for the detection of methane can be reduced to 300 °C by using Au–Pd nanoparticles on mesoporous cobalt oxide (Au–Pd@meso-Co3O4). The aim is to reduce possible catalyst poisoning that occurs during the high-temperature operation of conventional Pd-based pellistors, which are usually operated...

High activity of a catalyst and its thermal stability over a lifetime are essential for catalytic applications, including catalytic gas sensors. Highly porous materials are attractive to support metal catalysts because they can carry a large quantity of well-dispersed metal nanoparticles, which are well-accessible for reactants. The present work in...

In this work, we have investigated the influence of mechanical strain induced by passivation layers on the electrical performance of AlGaN/GaN HFETs. We studied the physical mechanism of a threshold voltage (Vth) shift for the monolithically fabricated on/off devices reported by our group in [1]. For that, theoretical calculations, simulation‐based...

This presentation is an introduction to machine learning techniques and their application in semiconductor failure analysis. The presentation compares and contrasts supervised, unsupervised, and reinforcement learning methods, particularly for neural networks, and lays out the steps of a typical machine learning workflow, including the assessment o...

The paper presents the approach of enhancing time-domain signal analysis using machine learning techniques for analyzing acoustic echo signals and the subsequent derivation of condition-related class assignments for failure analysis. The examples provided here include two types of flip-chips with defects intentionally induced by thermal stressing....

Developing high quality GaN/dielectric interfaces is a fundamental step for manufacturing GaN vertical power transistors. In this paper, we quantitatively investigate the effect of planar etching treatment and trench formation on the performance of GaN-based MOS (metal oxide semiconductor) stacks. The results demonstrate that (i) blanket etching th...

Developing high quality GaN/dielectric interfaces is a fundamental step for manufacturing GaN vertical power transistors. In this paper, we quantitatively investigate the effect of planar etching treatment and trench formation on the performance of GaN-based MOS (metal oxide semiconductor) stacks. The results demonstrate that (i) blanket etching th...

We investigate the effectiveness of laser-induced treatment as compared to rapid-thermal annealing (RTA) for the activation of p-type dopant in Mg-doped GaN layers. The study is based on a wide set of analytical techniques, including resistivity measurements, atomic force microscopy, scanning emission microscopy (SEM), dynamic secondary ion mass sp...

This paper reports the failure modes and degradation mechanism of normally-on AlGaN/GaN HEMTs of 150 nm gate length (GH15) with 2nd Generation metallization schemes Pt/Au, which provides more stable Schottky contact. Results show the device performance and final degradation under reverse bias OFF-state stressing at high VDS (145V). Electrical stres...

This presentation is an introduction to machine learning techniques and their application in semiconductor failure analysis. The presentation compares and contrasts supervised, unsupervised, and reinforcement learning methods, particularly for neural networks, and lays out the steps of a typical machine learning workflow, including the assessment o...

Lock-In Thermography is an established non-destructively operating method for the analysis of failures in microelectronic devices. In recent years a major improvement was achieved allowing the acquisition of the time-resolved temperature responses of weak thermal spots that enhances defect localization in 3D stacked semiconductor architectures. The...

The fabrication of pressure sensor dies for precise and stable industrial applications requires a critical high dose implantation process strongly affecting the manufacturing yield of these devices. This paper describes a specific critical process related failure mechanism caused by this implantation process generating local electrical shorts withi...

The vertical Gallium Nitride-on-Silicon (GaN-on-Si) trench metal-oxide-semiconductor field effect transistor (MOSFET) is a promising architecture for the development of efficient GaN-based power transistors on foreign substrates for power conversion applications. This work presents an overview of recent case studies, to discuss the most relevant ch...

The field of computer hardware stands at the verge of a revolution driven by recent breakthroughs in emerging nanodevices. 'Nano Security' is a new Priority Program recently approved by DFG, the German Research Council. This initial-stage project initiative at the crossroads of nano-electronics and hardware-oriented security includes 11 projects wi...

AlScN/GaN epitaxial heterostructures have raised much interest in recent years, because of the high potential of such structures for high-frequency and high-power electronic applications. Compared to conventional AlGaN/GaN heterostructures, the high spontaneous and piezoelectric polarization of AlScN can yield to a five-time increase in sheet carri...

In this article, we present the results of on-wafer short-term (24 h) stress tests carried out on 0.25- $\mu \text{m}$ AlGaN/GaN HEMTs. Devices on-wafer were submitted to 24-h dc tests, at various gate and drain voltage values corresponding to dissipated power densities ${P}_{D}$ up to 40 W/mm, with estimated channel temperature $\cong$ 375 °C...

Signal processing and data interpretation in scanning acoustic microscopy is often challenging and based on the subjective decisions of the operator, making the defect classification results prone to human error. The aim of this work was to combine unsupervised and supervised machine learning techniques for feature extraction and image segmentation...

Lock-in thermography (LIT) has been successfully applied in different excitation and analysis modes including classical LIT, analysis of the time-resolved temperature response (TRTR) upon square wave excitation and TRTR analysis in combination with arbitrary waveform stimulation. The results obtained by both classical square wave- and arbitrary wav...

The working temperature of pellistors using 3-dimensional mesoporous Co 3 O 4 (meso-Co 3 O 4 ) supported Au-Pd, Au-Pd@meso-Co 3 O 4 , is significantly reduced to 300 °C, thereby avoiding possible catalytic poisoning at high temperatures inherent in conventional pellistors. Our results indicate that meso-Co 3 O 4 has a great advantage over the comme...

For the first time a non-invasive localisation of a soft breakdown (SBD) is shown. The localisation is completed on fully functional back end of line (BEOL) test structures. The test structures used, provided by the interuniversity microelectronics centre (imec), are metal insulator semiconductor (MIS) structures. The low k dielectric within the te...

GHz scanning acoustic microscopy (GHz-SAM) was successfully applied for non-destructive evaluation of the integrity of back end of line (BEOL) stacks located underneath wire-bond pads. The current study investigated two sample types of different IC processes. Realistic bonding defects were artificially induced into samples and the sensitivity of th...

Engineers at the Fraunhofer Institute for Microstructure of Materials and Systems built and are testing a scanning acoustic microscope (SAM) that operates at frequencies of up to 2 GHz. Here they describe the design of their GHz-SAM and present examples showing how it is used to detect stress induced voids, inspect wire bond interfaces, and examine...

A new thermal model based on a distributed and fast modeling approach for the modeling of gallium nitride (GaN) power devices is presented in this paper. The model is based on the application of Green's function theory to obtain an analytical solution of the heat conduction equation. The model comprises an accurate, spatially distributed, and fast...

Through silicon via (TSV) is the most promising technology for vertical system integration and novel 3-D chip architectures. Reliability and quality assessment necessary for process development, root-cause analysis, and manufacturing require appropriate nondestructive testing techniques to achieve high processing yield and reliability. This paper p...

Tremendous research efforts have been devoted particularly to the development and improvement of through silicon vias (TSV) in order to provide a key enabling technology for vertical system integration. To achieve high processing yield and reliability efficient failure analysis techniques for process control and root cause analysis are required. Th...

Through Silicon Via (TSV) is the most promising technology for vertical interconnection in novel three-dimensional chip architectures. Reliability and quality assessment necessary for process development and manufacturing require appropriate non-destructive testing techniques to detect cracks and delamination defects with sufficient penetration and...

The performance of normally-off Gallium-Nitride (GaN) High-Electron-Mobility-Transistors (HEMTs) under extended short circuit operation is investigated. A thermal limit is found in the aluminium metallization, where at temperatures around 600 °C a protrusion of the gate metal through the Inter-Level Dielectric (ILD) may form, short-circuiting gate...

A low ohmic contact resistance is a key request on AlGaN/GaN HEMT devices especially when dealing with higher frequency applications. In such a GaN material system very high annealing temperatures of up to 900 °C are frequently necessary to achieve low ohmic resistance. It is known that high annealing temperatures could reduce electrical performanc...

A scanning transmission electron microscopy and an energy dispersive X-ray analysis of one non-annealed and one annealed sample (423 K for 4 hours) was performed. The results showed small and large voids appearing within the non-annealed and annealed samples respectively. In addition, chlorine segregated from the bulk into the voids. Ab initio calc...

High Electron Mobility Transistors (HEMTs) based on AlGaN/GaN are of great interest due to their high electrical performance and the related applications. The high carrier density, electron mobility, breakdown voltage, and the good thermal stability of AlGaN/GaN are great benefits for high power and high frequency technologies. The high electron mo...

Silicon based semiconductor devices are stressed during fabrication, handling and packaging with significant thermal and mechanical loadings. In worst cases, these induced loadings can cause initial chip damage leading to electrical failure or fracture of the Si-die during further process steps or application. In order to evaluate the risk of pre-d...

Silicon based semiconductor devices are stressed during fabrication, handling and packaging with significant thermal and mechanical loadings. In worst cases, these induced loadings can cause initial chip damage leading to electrical failure or fracture of the Si-die during further process steps or application. In order to evaluate the risk of pre-d...

GaN/AlGaN HEMT structures are observed to undergo a reversible, drastic change in the leakage current when covered with an additional polymer passivation layer. The polymer layer induces a stress on the HEMT structures, which initiates material migration processes and the formation of structural defects, influencing the electrical performance. Loca...

In the current paper the application of a custom developed 2-dimenional scanning magnetic field microscope based on tunnel-magnetoresistive sensors and subsequent qualitative and quantitative analysis is described. To improve sensitivity and to enable the detection and evaluation of phase deviations, an off-line lock-in approach was employed by dri...

Semiconductor devices used in automotive applications undergo numerous stress situations depending on their particular application. Corrosion, as one main crucial failure mechanisms, can affect the lifetime of electronic components on system, device or even die level. In this paper, a novel corrosion mechanism on HALL sensor devices is investigated...

Physical failure analysis (PFA) gives unparalleled insight into the nature of microelectronic structures and their defects. Developments in 3-D integration and packaging techniques challenge the conventional PFA techniques and require new approaches. This article provides an overview of recent results in this domain achieved at Fraunhofer IWM.

Several applications in the fields of industrial sensors and power electronics are creating a demand for high operating temperature of 300 °C or even higher. Due to the increased temperature range new potential defect risks and material interactions have to be considered. As a consequence, innovation in semiconductor, devices and packaging technolo...

In this paper we will demonstrate new approaches for failure analysis of memory devices with multiple stacked dies and TSV interconnects. Therefore, TSV specific failure modes are studied on daisy chain test samples. Two analysis flows for defect localization implementing Electron Beam Induced Current (EBAC) imaging and Lock-in-Thermography (LIT) a...

Long-term stability and reliability of AlGaN/GaN high electron mobility transistors (HEMT) can be validated by various stress tests which allow studying the physical mechanisms responsible for degradation. As the electroluminescence (EL) intensity is related to the kinetic energy and density of the channel electrons accelerated in the electric fiel...

3D-integration is one of the most challenging approaches addressed by researchers in the field of microelectronics in the recent years. With the intension on integrating different components in three dimensions in one device performance and functionality will increase dramatically by reducing the devices footprint. A major challenge in 3D-integrati...

In this paper advanced sample preparation techniques based on focused ion beam (FIB) optimized for TEM investigation of high electron mobility transistor (HEMT) structures are presented. It is shown that the usage of an innovative in-situ lift-out method combined with X2 window and backside milling techniques as well as live thickness control and e...

Currently smart cards with integrated silicon dies have found wide application for personal authorization, security identification and payment systems. As a consequence, the complexity of electronics is increasing, thus, specifically adapted failure analysis methods and work flows are required taking the peculiarities of smart card constructions wi...

Organic light emitting diodes (OLEDs) based display technologies are getting more and more important for smartphones, laptops and televisions. OLED devices consist of thin organic layer stacks between two electrodes. Located around an emission layer, where the radiative recombination of electrons and holes takes place, are layers for the transport...

Today three-dimensional system-in-package integration together with advanced interconnect technologies based on through silicon vias, through encapsulant vias, and microbumps are considered some of the most promising enabling technologies for "More than Moore" solutions. These technologies involve vertical die stacking or chip embedding with high-d...

The dimensions of microbumps in three-dimensional integration reach microscopic scales and thus necessitate a study of the multiscale microstructures in microbumps. Here, we present simulated mesoscale and atomic-scale microstructures of microbumps using phase field and phase field crystal models. Coupled microstructure, mechanical stress, and elec...

Within this paper the application potential of a new fast Plasma FIB system for defect analysis regarding packaging reliability studies is evaluated. Depending on the material under investigation both the higher current and the higher sputter efficiency of the Xe significantly improve the range of application fields and/or the analysis throughput....

In this paper, investigations on absolute temperature measurements using IR-Thermography of CMOS integrated micro-hot-plates (μHP) are presented. The results of using two different approaches, emissivity correction and black paint coating, are presented and compared with respect to simulation and electrical testing results. In addition, FIB/SEM inv...

Lock-in thermography and magnetic current imaging are emerging as the two image-based fault isolation methods most capable of meeting the challenges of short and open defect localization in thick, opaque assemblies. Such devices are rapidly becoming prevalent as 3D integration begins to ramp up production. This paper expands on previously published...

In this paper a novel approach for precise localisation of thin oxide breakdowns in transistor or capacitor structures by electron beam absorbed current (EBAC) imaging based on Scanning Electron Microscopy will be presented. The technique significantly improves sensitivity and lateral resolution of short localisation in comparison to standard techn...

New semiconductor chip technologies and technologies for 3D integration require information’s of packaging and interface defects in 3 dimensions, that means the lateral dimension of the defect and the location inside the device or package must be defined. In this paper, new methodical approaches for non destructive failure analysis on 3D integrated...

In this paper advanced techniques for dopant contrast imaging based on Scanning Electron Microscopy will be presented. It will be shown that biasing the pn-junction of Silicon based dopant structures significantly improves the sensitivity for dopant contrast imaging thus allowing to investigate low doped regions as well as sub-μm scaled dopant prof...

Lock-in thermography (LIT), which is a well established technique for non-destructive evaluation, can also be used to identify and locate thermal active electrically defects like shorts and resistive opens in microelectronic devices. Defect localization on the level of the integrated circuits (IC) requires a μm resolution. But LIT can also be appli...

An AlGaN/GaN high electron mobility transistor (HEMT) stressed at 10 GHz and increased channel temperatures of T ≈ 260 °C has been analyzed by electroluminescence microscopy (ELM) and infrared thermography (IRT). After stress a negative threshold shift is seen in the electrical characteristics. Based on the current dependence of the electroluminesc...

Newly developed techniques suitable and adapted to the needs of physical failure analysis of highly integrated 3-D SiP (System-in-Package) devices are reviewed. Scanning acoustic microscopy (SAM) is a powerful tool for nondestructive investigation of internal structures in optically opaque materials and typically provides a spatial resolution on th...

In this paper a novel approach for precise localisation of thin oxide breakdowns in transistor or capacitor structures by electron beam absorbed current (EBAC) imaging based on Scanning Electron Microscopy will be presented. The technique significantly improves sensitivity and lateral resolution of short localisation in comparison to standard techn...

With the growing variety, complexity and market share of 3D packaged devices, package level FA is also facing new challenges and higher demand. This paper presents Lock-In Thermography (LIT) for fully non-destructive 3D defect localization of electrical active defects. After a short introduction of the basic LIT theory, two slightly different appro...

It was already demonstrated, that the method of Lock-in Thermography (LIT) enables 3D localization of thermal active defects, e.g. electrical shorts and resistive opens, on die level and within fully packaged single and multichip devices [1,2]. The depth of a defect can be derived from phase shift measurements of the defective compared to a referen...