Combining Electron Beam Methods, EBIC and EBAC, with Traditional Approaches for Highly Effective Fault Isolation

Author(s):  
Ryan Fredrickson ◽  
Tim Kuebrich ◽  
Andrew Le ◽  
Derek Snider ◽  
Lucas Winiarski

Abstract Fault isolation is an important initial component of the failure analysis investigation as it provides the first indicator of the defect physical location. The most broadly familiar fault isolation techniques include photoemission microscopy (PEM), optical beam induced resistance change (OBIRCH) and liquid crystal analysis (LCA). Each of these techniques has their own strengths but also drawbacks which can impede the analysis by either not providing a well isolated defect location or causing damage to the defect region. For some types of defects, photoemission and liquid crystal analysis may create local heating of the device which can distort the defect and mask the root cause of the failure. These techniques also rely on optical microscopy which has low resolution compared to the feature size of current technologies. In addition, each technique may not highlight the defect site itself; only pointing the analyst to the defective circuit within the sample. Electron Beam Induced Current (EBIC) and Electron Beam Absorbed Current (EBAC) microscopy provides solutions to these complications. In this paper we describe some very effective approaches by using these beam-based techniques in conjunction with traditional methods. As introduction, we have provided some interesting case studies whereby EBIC/EBAC have been used in conjunction with FIB circuit edits and scan diagnostic results to narrow the defect search areas. We focus the paper on some less common applications of cross sectional EBIC/EBAC as well as utilizing an AC coupled configuration to activate more subtle defect sites. We conclude with two examples where AC coupled cross-sectional EBIC is needed to highlight the cause of the failure.

Author(s):  
Chi-Lin Huang ◽  
Yu Hsiang Shu

Abstract Conventional isolation techniques, such as Optical Beam Induced Resistance Change (OBIRCH) or photoemission microscopy (PEM) frequently fail to locate failure points when only applied to power pin of the semiconductor device. In this paper, a novel OBIRCH failure isolation technique is utilized to detect leakage failures. Different test conditions are presented to identify the differences in current when all input pins are pulled high in an OBIRCH system. In order to verify a failure point, it is necessary to perform electrical analysis of the suspected failure point in the failing sample. In general, Conductive Atomic Force Microscope (C-AFM) and a Nano-Prober is sufficient to provide the electrical data required for failure analysis. Experiment results, however, prove that this novel OBIRCH failure isolation technique is effective in locating the failure point, especially for leakage failures. The failure mechanism is illustrated using cross-sectional TEM.


Author(s):  
Frank S. Arnold

Abstract To be better prepared to use laser based failure isolation techniques on field failures of complex integrated circuits, simple test structures without any failures can be used to study Optical Beam Induced Resistance Change (OBIRCH) results. In this article, four case studies are presented on the following test structures: metal strap, contact string, VIA string, and comb test structure. Several experiments were done to investigate why an OBIRCH image was seen in certain areas of a VIA string and not in others. One experiment showed the OBRICH variation was not related to the cooling and heating effects of the topology, or laser beam focusing. A 4 point probe resistance measurement and cross-sectional views correlated with the OBIRCH results and proved OBIRCH was able to detect a variation in VIA fabrication.


Author(s):  
Brett A. Buchea ◽  
Christopher S. Butler ◽  
H.J. Ryu ◽  
Wen-hsien Chuang ◽  
Martin von Haartman ◽  
...  

Abstract A novel fault isolation technique, electron beam induced resistance change (EBIRCh), allows for the direct stimulation and localization of eBeam current sensitive defects with resolution of approximately 100nm square, continuing a history of beam based failure isolation methods. EBIRCh has been shown to work over a range of defects, significantly decreasing the time required for isolation of shorts through straightforward high resolution imagery, allowing for explicit visual defect isolation with a linear resolution of approximately 10nm. This paper discusses the operational setups for the source and amplifier while performing an EBIRCh scan, describes the processes involved in the Intel test vehicle that was used to test EBIRCh, and provides information on two independent functional theories for EBIRCh that operate in conjunction to a greater or lesser extent depending on the defect type. EBIRCh is expected to improve through-put and resolution on various defect types compared to conventional fault isolation techniques.


Author(s):  
Jim Douglass ◽  
Sohrab Pourmand

Abstract This paper shows that by combining electrical fault isolation and characterization by microprobing with physical fault isolation techniques both what is wrong with the circuit and where the defect is located can be determined with less microprobing and more safety from electrical recovery. In the first example, the unit was powered up using the optical beam induced resistance change (OBIRCH) supply, and OBIRCH was performed to determine if there were OBIRCH site differences between the good part and the return. The second example uses a combination of electrical fault isolation and characterization with microprobing and the physical fault isolation tool of lock in thermography (LIT). With these two examples, it has been shown that the use of electrical fault isolation and microprobing can be used to enhance the physical fault isolation tools of OBIRCH and LIT.


Author(s):  
Ikuo Arata ◽  
Shigeru Sakamoto ◽  
Yoshiyuki Yokoyama ◽  
Hirotoshi Terada

Abstract SIL(Solid Immersion Lens) is well investigated for optical pickup application because of its capability of high resolution. We applied this technique to microscopy, especially for precise observation of semiconductors. And also we applied it to fault isolation techniques like emission microscopy , OBIRCH(Optical Beam Induced Resistance Change) and TIVA,SEI. We found significant enhancement of resolution and sensitvity by using SIL. Applying this technique to emission microscopy, we should be aware of optical absorption charactristics of SIL lens materials. We investigated proper SIL lens materials for emission microscopy and laser scanning applications, and checked performance of Si(Silicon)-SIL and GaP(Gallium phosphide)-SIL. We also compared combinations of some kinds of SILs and detectors like C-CCD(cooled CCD) camera, MCT(HgCdTe) camera and position sensitive detector with InGaAs photo cathode II(image intensifier).


2021 ◽  
Author(s):  
Lori L. Sarnecki ◽  
Regina Kuan

Abstract The integrity of a P-type or N-type epitaxial layer, implanted wells, or dopants (i.e. P-epi, N-well, P-imp, N-imp, etc.) oftentimes can affect the performance of an integrated circuit (IC), especially in analog/mixed signal devices. At onsemi, we had encountered a poor P-N junction of a Zener diode that caused a Cross-Coupled-Switched-Cap voltage doubler to have a lower output voltage which eventually affected the performance of the IC. The integrity of any P-N junction can be electrically verified through curve tracing with in-SEM nano-probing and fault isolation (PEM, OBIRCH, etc.) techniques. However, physical defect revelation using junction stain, either top-down or in cross section, can be challenging due to the three-dimensional (3D) form of any P-N junction. With Electron Beam Induced Current (EBIC), we can easily identify an abnormal P-N junction through both topdown and cross section. This paper is to characterize EBIC analysis on IC cross sectional view in mapping the P-N junctions and provide the information of its doping profiles. In this paper, limitation of both chemical etching and EBIC will be discussed as well as introducing the use of ion mill after FIB cross section during cross sectional EBIC sample prep as a potential method for resolution enhancement. These findings add to the understanding in using this technique and further improvement to its application in failure analysis.


2018 ◽  
Author(s):  
Yu-Xiu Chen ◽  
Pei-Ning Hsu ◽  
Yu-Min Chung ◽  
Hsin-Cheng Hsu ◽  
Huai-San Ku ◽  
...  

Abstract A recently developed technique known as Electron Beam Induced Resistance Change (EBIRCH) equipped with a scanning electron microscope (SEM) utilizes a constant electron beam (e-beam) voltage across or current through the defect of interest and amplifies its resistance variation. In this study, EBIRCH is applied for a 3D NAND structure device fault isolation but suffered from nearby dielectric film deformation. The characterization of such dielectric deformation and the possible mechanisms of e-beam induced damage are discussed. As well, a threshold condition to avoid from triggering the occurrence of dielectric damage is presented for shallow defect analysis in EBIRCH application.


Author(s):  
Jeffrey Javier ◽  
Taylor Hurdle ◽  
Sammie Fernandez ◽  
Kari Van Vliet

Abstract The increasing electrical design and physical complexity of semiconductor devices, especially in the analog and mixed signal (AMS) applications, directly influences the development and evolution of fault isolation techniques. One of these techniques is Dynamic Laser Stimulation (DLS) which is widely used in the industry for effective identification of subtle failure mechanisms and soft defects especially for AC signal-related failures [1, 2]. However, for analysis of some complex AMS IC failure modes, the tool’s standard setup may not always be compatible with the biasing requirements of the device. For example, the setup would typically require expensive and intricate test systems (i.e. Automatic test equipment (ATE), SCAN tester, etc.) to be interfaced with the DLS tool for the analysis to be feasible and successful [3, 4]. This paper presents simple and practical techniques to implement DLS without the need for an expensive test support system. These techniques were applied in three different FA cases involving AMS ICs with complex and temperature-dependent failure modes. The results of subsequent analysis indicated success in isolating the exact defect sites.


Author(s):  
W. Brünger

Reconstructive tomography is a new technique in diagnostic radiology for imaging cross-sectional planes of the human body /1/. A collimated beam of X-rays is scanned through a thin slice of the body and the transmitted intensity is recorded by a detector giving a linear shadow graph or projection (see fig. 1). Many of these projections at different angles are used to reconstruct the body-layer, usually with the aid of a computer. The picture element size of present tomographic scanners is approximately 1.1 mm2.Micro tomography can be realized using the very fine X-ray source generated by the focused electron beam of a scanning electron microscope (see fig. 2). The translation of the X-ray source is done by a line scan of the electron beam on a polished target surface /2/. Projections at different angles are produced by rotating the object.During the registration of a single scan the electron beam is deflected in one direction only, while both deflections are operating in the display tube.


Author(s):  
Ryo Iiyoshi ◽  
Susumu Maruse ◽  
Hideo Takematsu

Point cathode electron gun with high brightness and long cathode life has been developed. In this gun, a straightened tungsten wire is used as the point cathode, and the tip is locally heated to higher temperatures by electron beam bombardment. The high brightness operation and some findings on the local heating are presented.Gun construction is shown in Fig.l. Small heater assembly (annular electron gun: 5 keV, 1 mA) is set inside the Wehnelt electrode. The heater provides a disk-shaped bombarding electron beam focusing onto the cathode tip. The cathode is the tungsten wire of 0.1 mm in diameter. The tip temperature is raised to the melting point (3,650 K) at the beam power of 5 W, without any serious problem of secondary electrons for the gun operation. Figure 2 shows the cathode after a long time operation at high temperatures, or high brightnesses. Evaporation occurs at the tip, and the tip part retains a conical shape. The cathode can be used for a long period of time. The tip apex keeps the radius of curvature of 0.4 μm at 3,000 K and 0.3 μm at 3,200 K. The gun provides the stable beam up to the brightness of 6.4×106 A/cm2sr (3,150 K) at the accelerating voltage of 50 kV. At 3.4×l06 A/cm2sr (3,040 K), the tip recedes at a slow rate (26 μm/h), so that the effect can be offset by adjusting the Wehnelt bias voltage. The tip temperature is decreased as the tip moves out from the original position, but it can be kept at constant by increasing the bombarding beam power. This way of operation is possible for 10 h. A stepwise movement of the cathode is enough for the subsequent operation. Higher brightness operations with the rapid receding rates of the tip may be improved by a continuous movement of the wire cathode during the operations. Figure 3 shows the relation between the beam brightness, the tip receding rate by evaporation (αis the half-angle of the tip cone), and the cathode life per unit length, as a function of the cathode temperature. The working life of the point cathode is greatly improved by the local heating.


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