Magneto-Optical Frequency Mapping System for Very Low Resistance Short Circuit Failure Imaging

2015 ◽  
Author(s):  
Tomonori Nakamura
Keyword(s):  
Quantum Interference ◽  
Short Circuit ◽  
Ease Of Use ◽  
Lower Sensitivity ◽  
Imaging Method ◽  
Crystal Thickness ◽  
Low Resistance ◽  
Current Path ◽  
Gmr Sensor ◽  
Failure Localization

Abstract Magnetic field imaging (MFI) has been an excellent tool for a low resistance failure localization in LSI devices. A Superconducting Quantum Interference Device (SQUID) and a Giant Magneto Resistive (GMR) sensor are well known in this field. A SQUID has extremely high magnetic sensitivity (500 nA, <40 pT/ √Hz)[1], but the spatial resolution is somewhat problematic due to the clearance that is needed for cooling and vacuuming mechanism. A GMR sensor has higher resolution but lower sensitivity (50 uA, <10 nT/√Hz)[1] and, they have less flexibility because the sensor/stage has to be scanned during operation. In this paper, we present a new current imaging method called Magneto-Optical (MO) Frequency Mapping (MOFM). The imaging is based on a laser beam scanning, which allows flexibility and ease of use. The MO signal intensity is inversely proportional to the distance between the sensor and the current path to be detected. Since it can be 10 um or less, i.e., one half of the MO crystal thickness, it practically makes the MOFM’s system sensitivity is 10 uA, it only 20 times lower than a SQUID method, even though the intrinsic sensitivity may be about 250 times or so lower. It can also achieve high special resolution as with the GMR sensor because of the short distance or clearance needed to sense the current. These characteristics are verified with a TEG sample and we present a case in which it is applied for the short circuit failure localization.

Magnetic Current Imaging of a TSV short in a 3D IC

2015 ◽  
Vol 2015 (DPC) ◽  
pp. 001408-001428
Author(s):  
Jan Gaudestad ◽  
Antonio Orozco
Keyword(s):  
Quantum Interference ◽  
Semiconductor Industry ◽  
Fault Isolation ◽  
Magnetic Current ◽  
Current Path ◽  
Fine Pitch ◽  
Dual Beam ◽  
Gmr Sensor ◽  
Test Chips ◽  
Chip Chip

In this paper we show Magnetic Field Imaging (MFI) is the best method for Electric Fault Isolation (EFI) of short failures in 2.5/3D Through Silicon Via (TSV) devices in a true non-destructive way by imaging the current path. To confirm the failing locations and to do Physical Failure Analysis (PFA), a Dual Beam-Plasma FIB (DB-PFIB) system was used for cross sectioning and volume analysis of the TSV structures and high resolution imaging of the identified defects. Magnetic Current Imaging (MCI) is a sub technique of MFI which has been used by the semiconductor industry for more than a decade to find electrical shorts and leakage paths and which has the capability to “look through” all materials typically used in the semiconductor industry, allowing global imaging without the need for physical de-processing [1, 2, 3]. MCI utilizes two types of sensors: a Superconducting Quantum Interference Device (SQUID) sensor for low current and large working distances and a Giant Magneto Resistance (GMR) sensor for sub micron resolution current imaging at wafer/die level [3]. The sample investigated in this work is a triple-layer stack, in which 2 layers of 50 μm thick test chip (Chip 1 and Chip 2 in Figure 1) were assembled on a 200 μm thick bottom chip (Chip 0 in Figure 1). The test chips were manufactured by imec's standard 65 nm CMOS Back End of Line (BEOL) process, 5×50 μm via-middle TSV technology [4], and fine pitch micro bumping process [6]. Further details of the test vehicle and assembly process can be found elsewhere [5]. The sample had a short between daisy chain a1 and a2, which were supposed to be electrically separated. The probe tests that was used for this experiment is shown in Table 1. The signal was injected into the respective daisy chains by probing V+ to V− on the bottom chip. To send a signal between daisy chain a1 and a2 one could probe V− to V− and V+ to V+. The MCI scans were done using the GMR sensor only. The sample was attached to a vacuum chuck and raster scanned. From Fig. 2 one can see that the current enters the top layer (Chip 2) at TSV 18 and goes back down again to Chip 1 at TSV 28. Since the sample clearly has multiple shorts, the short located at TSV pair 23 was chosen for PFA using the PFIB. A short is found between the 2 BEOL layers of Chip 1, causing the current to leak into Chip 2 (Fig. 3).

scholarly journals An Intelligent Electronic Fuse (iFuse) to Enable Short-Circuit Fault-Tolerant Operation of Power Electronic Converters

2020 ◽  
Author(s):  
Alber Filba-Martinez ◽  
Salvador Alepuz ◽  
Sergio Busquets-Monge ◽  
Adria Luque ◽  
Josep Bordonau
Keyword(s):  
Fault Tolerant ◽  
Short Circuit ◽  
Failure Detection ◽  
Experimental Tests ◽  
Power Electronic Converters ◽  
Novel Device ◽  
Current Path ◽  
In Series ◽  
Short Circuit Fault ◽  
Short Circuit Currents

The present paper proposes a novel device defined as an intelligent electronic fuse (iFuse) meant to be connected in series with any current-bidirectional voltage-unidirectional active switch present in a given converter. The iFuse duty is to isolate its series- associated switch from the rest of the converter circuit immediately after detecting that said switch has failed in short circuit. Nonetheless, it maintains the reverse (free- wheeling) current path originally offered by the failed switch. The failure detection is performed when the failed switch causes a shoot-through event. Therefore, the iFuse is designed to be able to block the elevated current occurring in such event. The iFuse allows increasing the fault-tolerant capability and the reliability of power converters where such qualities are hindered by switch short-circuit failures, as in converters featuring parallelized switches, neutral-point-clamped multilevel topologies, or redundant legs. The feasibility of the iFuse device is verified through experimental tests, proving that the device is able to detect the failure of its associated switch and isolate it from the rest of the converter circuit in 6 μs, while stopping short-circuit currents of up to 1 kA without incurring in harmful di/dt values.

scholarly journals T2Candida Assay in the Diagnosis of Intraabdominal Candidiasis: A Prospective Multicenter Study

2022 ◽  
Vol 8 (1) ◽  
pp. 86
Author(s):  
Anders Krifors ◽  
Måns Ullberg ◽  
Markus Castegren ◽  
Johan Petersson ◽  
Ernesto Sparrelid ◽  
...  
Keyword(s):  
Predictive Value ◽  
Pathogen Detection ◽  
Necrotizing Pancreatitis ◽  
Gastrointestinal Surgery ◽  
Dual Infection ◽  
Ease Of Use ◽  
Lower Sensitivity ◽  
High Dependency ◽  
Detection Assay ◽  
Sensitivity Specificity

The T2Candida magnetic resonance assay is a direct-from-blood pathogen detection assay that delivers a result within 3–5 h, targeting the most clinically relevant Candida species. Between February 2019 and March 2021, the study included consecutive patients aged >18 years admitted to an intensive care unit or surgical high-dependency unit due to gastrointestinal surgery or necrotizing pancreatitis and from whom diagnostic blood cultures were obtained. Blood samples were tested in parallel with T2Candida and 1,3-β-D-glucan. Of 134 evaluable patients, 13 (10%) were classified as having proven intraabdominal candidiasis (IAC) according to the EORTC/MSG criteria. Two of the thirteen patients (15%) had concurrent candidemia. The sensitivity, specificity, positive predictive value, and negative predictive value, respectively, were 46%, 97%, 61%, and 94% for T2Candida and 85%, 83%, 36%, and 98% for 1,3-β-D-glucan. All positive T2Candida results were consistent with the culture results at the species level, except for one case of dual infection. The performance of T2Candida was comparable with that of 1,3-β-D-glucan for candidemic IAC but had a lower sensitivity for non-candidemic IAC (36% vs. 82%). In conclusion, T2Candida may be a valuable complement to 1,3-β-D-glucan in the clinical management of high-risk surgical patients because of its rapid results and ease of use.

scholarly journals Diagnostic accuracy of two commercial SARS-CoV-2 antigen-detecting rapid tests at the point of care in community-based testing centers

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0248921
Author(s):  
Alice Berger ◽  
Marie Therese Ngo Nsoga ◽  
Francisco Javier Perez-Rodriguez ◽  
Yasmine Abi Aad ◽  
Pascale Sattonnet-Roche ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Point Of Care ◽  
Rapid Test ◽  
Diagnostic Value ◽  
Ease Of Use ◽  
Lower Sensitivity ◽  
Rt Pcr ◽  
Test Device ◽  
Community Based ◽  
Rapid Tests

Objectives Determine the diagnostic accuracy of two antigen-detecting rapid diagnostic tests (Ag-RDT) for SARS-CoV-2 at the point of care and define individuals’ characteristics providing best performance. Methods We performed a prospective, single-center, point of care validation of two Ag-RDT in comparison to RT-PCR on nasopharyngeal swabs. Results Between October 9th and 23rd, 2020, 1064 participants were enrolled. The PanbioTM Covid-19 Ag Rapid Test device (Abbott) was validated in 535 participants, with 106 positive Ag-RDT results out of 124 positive RT-PCR individuals, yielding a sensitivity of 85.5% (95% CI: 78.0–91.2). Specificity was 100.0% (95% CI: 99.1–100) in 411 RT-PCR negative individuals. The Standard Q Ag-RDT (SD Biosensor, Roche) was validated in 529 participants, with 170 positive Ag-RDT results out of 191 positive RT-PCR individuals, yielding a sensitivity of 89.0% (95%CI: 83.7–93.1). One false positive result was obtained in 338 RT-PCR negative individuals, yielding a specificity of 99.7% (95%CI: 98.4–100). For individuals presenting with fever 1–5 days post symptom onset, combined Ag-RDT sensitivity was above 95%. Lower sensitivity of 88.2% was seen on the same day of symptom development (day 0). Conclusions We provide an independent validation of two widely available commercial Ag-RDTs, both meeting WHO criteria of ≥80% sensitivity and ≥97% specificity. Although less sensitive than RT-PCR, these assays could be beneficial due to their rapid results, ease of use, and independence from existing laboratory structures. Testing criteria focusing on patients with typical symptoms in their early symptomatic period onset could further increase diagnostic value.

Radioactive and Non-Radioactive In Situ Hybridization Techniques

1996 ◽  
Vol 54 ◽  
pp. 8-9
Author(s):  
I. Durrant
Keyword(s):  
Biological Sciences ◽  
Selection Process ◽  
Disease Diagnosis ◽  
Ease Of Use ◽  
Lower Sensitivity ◽  
Probe Type ◽  
Oligonucleotide Probes ◽  
Rna Probes ◽  
In Cells

In situ hybridization is a powerful technique that has found multiple applications in the biological sciences. The most widely used technique is in the analysis of mRNA species in cell populations. This is particularly useful for the analysis of relative amounts, site of transcription, timing and induction of transcription. Recent advances have lead the technique into the areas of relative quantification, dual signal detection and disease diagnosis. DNA targets can also be visualised by in situ hybridization both in cells and tissues and on isolated chromosomes and nuclei. There are a variety of systems that can be used to detect hybridization signals in situ. These choices are based in two areas, probe type and label type and this selection process holds true for both radioactive and non-radioactive systems.Probe selection is important and plays a part in the overall success of the application (see Table 1). RNA probes and oligonucleotide probes are the most widely used in cells and tissues whereas DNA probes are routinely used for chromosome and nuclei targets. RNA probes are used due to the higher sensitivity obtained but oligonucleotide probes are gaining in popularity due to ease of use. The lower sensitivity seen with these probes, due to lower labelling capacity, can be overcome by use of probe cocktails.

Magnetic Field Imaging for 3D applications

2014 ◽  
Vol 2014 (DPC) ◽  
pp. 001937-001965
Author(s):  
Jan Gaudestad ◽  
Antonio Orozco
Keyword(s):  
Magnetic Field ◽  
Field Distribution ◽  
Quantum Interference ◽  
Device Fabrication ◽  
Fault Isolation ◽  
Current Path ◽  
Magnetic Field Imaging ◽  
The Magnetic Field ◽  
Field Imaging ◽  
A Current

The challenges that 3D integration present to Failure Analysis require the development of new Fault Isolation techniques that allows for non-destructive, true 3D failure localization. By injecting a current in the device under test (DUT), the current generates a magnetic field around it and this magnetic field is detected by a sensor above the device. Magnetic field imaging (MFI) is a natural candidate for 3D Fault Isolation of complex 3D interconnected devices. This is because the magnetic field generated by the currents in the DUT passes unaffected through all materials used in device fabrication; the presence of multiple metal layers, dies or other opaque layers do not have any impact on the magnetic field signal. The limitations of the technique are not affected by the number of layers in the stacked devise in samples such as wirebonded stacked memory, Through Silicon Via (TSV) stacked die or even package on package (PoP). The sample is raster scanned and magnetic field is acquired at determined steps providing a magnetic image of the field distribution. This magnetic field data is typically processed using a standard inversion technique to obtain a current density map of the device. The resulting current map can then be compared to a circuit diagram, an optical or infrared image, or a non-failing part to determine the fault location. Today, giant-magnetoresistive (GMR) sensors have been added to the Superconducting Quantum Interference Device (SQUID) sensor to allow higher resolution and Fault Isolation (FI) I at die level. Magnetic Field Imaging (MFI), using SQUID as the high sensitive magnetic sensor in combination with a high resolution GMR sensor. A solver algorithm capable of successfully reconstructing a 3D current path based on an acquired magnetic field image from both sensors has been developed. The generic 3D inverse problem has no unique solution. Given a particular 3D magnetic field distribution, there are an infinite number of current path distributions that will result in such magnetic field. This ill-posed problem has restricted, so far, the use of magnetic imaging to 2D. A different kind of 3D solver can be constructed, nevertheless capable of obtaining a single solution. The 3D solver algorithm is not only capable of extracting the 3D current path, but it also provides valuable geometrical information about the device. Accurately being able to position each current segment in a layer allows the FA engineer to follow the current as it vertically moves from one die (or layer) to another. [1,2,3]

Magnetic Microscopy for 3D Structures: Use of the Simulation Approach for the Precise Localization of Deep Buried Weak Currents

2010 ◽  
Author(s):  
Fulvio Infante ◽  
Rodolphe Gomes ◽  
Philippe Perdu ◽  
Fabien Battistella ◽  
Sebastien Annereau ◽  
...  
Keyword(s):  
Magnetic Measurements ◽  
Three Dimensional ◽  
New Method ◽  
Dimensional Structure ◽  
Precise Localization ◽  
Simulation Approach ◽  
Three Dimensional Structure ◽  
Current Path ◽  
A New Technique ◽  
Failure Localization

Abstract With the innovations in packaging technologies which have taken place over the last decade, new assemblies often include an increasing number of dies inside a single package. This is exactly what was predicted by the More than Moore’s paradigm: as the integration of ICs increases, the heterogeneity of the devices found in a single package increases. As a result, the number of potential failures which can appear at assembly level has increased exponentially. At present, no technique has been able to precisely localize defects which are deep inside a complex package. For this reason, a new technique for failure localization for three-dimensional structures is needed. In this paper the technique proposed, based on the coupling of magnetic measurements and simulations, is applied to a three-dimensional structure to precisely localize the current path which is buried deep inside it. A new method, based on parameters fittings of magnetic simulations, is then applied in order to accurately evaluate the distance between the current and the sensor.

Analysis of a Microcircuit Failure using SQUID and MR Current Imaging

2005 ◽  
Author(s):  
Frederick S. Felt
Keyword(s):  
Integrated Circuits ◽  
Thermal Emission ◽  
High Current Density ◽  
Fault Isolation ◽  
Magnetic Sensors ◽  
Nand Gate ◽  
Magnetic Current ◽  
Package Design ◽  
Low Resistance ◽  
Current Path

Abstract SQUID and MR magnetic sensors have separately been used for fault isolation of shorts and resistive opens in integrated circuits and packages. These two technologies were once considered to be mutually exclusive, although recent studies [1] rather pointed to their complementary character. This paper shows, for the first time, the use of these two sensors together to isolate a low resistance short in a Quad-NAND gate microcircuit. Electrical test confirmed low resistance shorts between three of the device pins. However, internal optical inspection found no evidence of failure. The low resistance of the shorts was deemed insufficient for liquid crystal analysis. Magnetic current imaging with a SQUID sensor confirmed current flow through the package lead frame and isolated the defect to the microcircuit. Due to package design and the resulting distance of the scan plane, the SQUID was unable to resolve the current path on the microcircuit. In parallel with the SQUID, a magnetoresistive (MR) probe was employed to fit inside the device cavity, make direct contact with the microcircuit, and map high-resolution current images. Two sites with high-current density were accurately identified by MCI in input transistors. Subsequent deprocessing revealed that the defects were located under a broad sheet of aluminum metallization which blocked optical detection, and rendered detection by thermal emission difficult.

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