bluuebunny/crossref_metadata_2025 huggingface dataset:
La urbanización de la Villa 31 en su contexto: un estado de la cuestión de la rehabilitación del barrio de Retiro (2015-2019)
Authors: Capalbo Tomás , Percossi Bossero Federico Leandro
Published: December 2020

La propuesta del artículo es indagar en torno a lo que se considera una novedad en el campo de las políticas públicas orientadas a las villas de la CABA: la coexistencia de urbanizaciones orientadas a promover la “integración” de barrios populares con megaproyectos públicos y privados de otra índole en zonas aledañas. Atendiendo uno de los casos que consideramos paradigmáticos a este respecto, se procede a situar el proceso de urbanización de la Villa 31 en el contexto de la rehabilitación del barrio de Retiro. En función de ello, se busca hacer una caracterización muy sucinta de los proyectos y políticas urbanísticas impulsados durante el período 2015-2019 en el barrio en cuestión, los cuales se pueden dividir de la siguiente manera: a) obras públicas tendientes a equipar, acondicionar y/o embellecer el área; b) venta de tierras públicas para el desarrollo inmobiliario y c) la integración de la Villa 31.
Implementasi Pendekatan Realistic Mathematic Education (RME) terhadap Hasil Belajar Penyajian Data di Sekolah Dasar
Authors: Putri Tika Yuanda , Ariani Yetti
Published: December 2020

Penelitian ini bertujuan untuk mendeskripsikan Pendekatan Realistic Mathematic Education (RME) terhadap hasil belajar pada materi penyajian data di Kelas IV Sekolah Dasar. Penelitian ini menggunakan metode studi literatur (Library Research). Sumber data sekunderyang terdapat di dalam artikel atau jurnal (tercetak dan/atau non-cetak) berkenaan dengan Pendekatan Realistic Mathematics Education (RME) Terhadap Hasil Belajar Penyajian Data di Sekolah Dasar. Hasil penelitian berupa analisis atau review 25 artikel yang relevan dengan masalah yang ada pada studi literatur ini. Dari hasil penelitian 25 artikel yang relevan menunjukkan bahwa hasil uji hipotesis menggunakan uji t(t hitung > t tabel) sehingga Ho ditolak dan Ha diterima. Dengan demikian, dapat diinterpretasikan bahwa terdapat hasil belajar matematika yang signifikan pada materi penyajian data antara kelompok siswa yang mengikuti pembelajaran dengan pendekatan Realistic Mathematic Education (RME) dengan kelompok siswa yang mengikuti pembelajaran dengan pendekatan pembelajaran konvensional pada siswa kelas IV Sekolah Dasar pada materi penyajian data.
Incidencia de queratitis fúngicas en el Hospital Nacional de Clínicas, Córdoba
Authors: Cepeda Burghini Romina , Fraenza Laura Beatriz
Published: December 2020

Resumen

Introducción: La queratitis fúngica es una infección corneal supurativa grave, generalmente ulcerosa, que puede provocar ceguera o visión reducida.

Objetivos: Reportar la incidencia y los agentes causales más comunes de queratitis micóticas en el Hospital Nacional de Clínicas, de la ciudad de Córdoba.

Materiales y Métodos: Se llevó a cabo un estudio retrospectivo, descriptivo y comparativo de los registros de casos con diagnóstico de queratitis fúngica en el Hospital Nacional de Clínicas en el período comprendido desde marzo del 2007 a diciembre de 2017 inclusive, analizando las variables edad, sexo y factores predisponentes. Se determinaron porcentajes y frecuencias de los microorganismos recuperados y llevando a cabo un análisis estadístico mediante una prueba de dependencia, determinamos la relación entre sexo de los pacientes e incidencia de queratitis fúngica.

Resultados: De los 66 casos positivos respecto de 469 muestras totales, el 57.5% correspondió a Fusarium sp, seguido de Aspergillus sp. La principal causa de queratitis fúngica fue traumatismo con restos de vegetales. Se determinó un promedio de 6 casos diagnosticados por año.

Conclusiones: El género predominante fue Fusarium sp, con una incidencia del 14,1% para esta infección en una proporción de 2.9:1 hombres respecto de mujeres.
HIST2H2AA3 is differentially expressed in the lymph node and brain metastases of patients with metastatic breast cancer.
Authors: Mamoor Shahan
Published: December 2020

Metastasis to the brain is a clinical problem in patients with breast cancer (1-3). We mined published microarray data (4, 5) to compare primary and metastatic tumor transcriptomes to discover genes associated with brain metastasis in patients with metastatic breast cancer. We found that the histone cluster 2, H2aa3, encoded by HIST2H2AA3 was among the genes whose expression was most different in the brain and lymph node metastases of patients with metastatic breast cancer as compared to primary tumors of the breast and normal breast tissues, respectively. HIST2H2AA3 mRNA was present at higher quantities in brain metastatic tissues as compared to primary tumors of the breast. These data combined suggest some level of common origin for metastases that reside in the lymph nodes and colonize the brain.
Localizing Heat-Generating Defects Using Fluorescent Microthermal Imaging
Authors: Tangyunyong P. , Liang A.Y. , Righter A.W. , Barton D.L. , Soden J.M.
Published: December 2020

Fluorescent microthermal imaging (FMI) involves coating a sample surface with a thin fluorescent film that, upon exposure to UV light source, emits temperature-dependent fluorescence [1-7]. The principle behind FMI was thoroughly reviewed at the ISTFA in 1994 [8, 9]. In two recent publications [10,11], we identified several factors in film preparation and data processing that dramatically improved the thermal resolution and sensitivity of FMI. These factors include signal averaging, the use of base mixture films, film stabilization and film curing. These findings significantly enhance the capability of FMI as a failure analysis tool. In this paper, we show several examples that use FMI to quickly localize heat-generating defects ("hot spots"). When used with other failure analysis techniques such as focused ion beam (FIB) cross sectioning and scanning electron microscope (SEM) imaging, we demonstrate that FMI is a powerful tool to efficiently identify the root cause of failures in complex ICs. In addition to defect localization, we use a failing IC to determine the sensitivity of FMI (i.e., the lowest power that can be detected) in an ideal situation where the defects are very localized and near the surface.
Failure Analysis of the Die-Attach in a Metal-Type Package
Authors: Acki J. , Murakami A. , Akutsu T. , Matsuda S. , Maruyama A. , Iwamoto T. , Kirihata H.
Published: December 2020

RECENTLY POWER MOSFETS have been used for satellite power supplies. NASDA has developed such a Power MOSFET for the space projects. It has a metal-type package, and the die is attached by Au-Si alloy to achieve high temperature operation (Tj=200°C). The fabricated device failure was detected thermal resistance tests after high temperature storage test at 200°C for 1000 hours. This failure is caused by the die peeling between the Au-Si eutectic alloy layer and the Ni plating surface on the Cu-W substrate. In this paper, we describe the failure mechanism and improvements in the package design and fabrication process. The newly developed power MOSFET for space use exhibits good performance in the high temperature storage test.
A CAD-Based Approach to Failure Diagnosis of CMOSLSI with Single Fault Using Abnormal IDDQ
Authors: Sanada M.
Published: December 2020

A CAD-based fault diagnosis technique for CMOS-LSI with single fault using abnormal IDDQ has been developed to indicate the presence of physical damage in a circuit. This method of progressively reducingthe faulty portion, works by extracting the inner logic state of each block from logic simulation, and by deriving test vector numbers with abnormal IDDQ. To easily perform fault diagnosis, the hierarchical circuit structure is divided into primitive blocks including simple logic gates. The diagnosis technique employs the comparative operation of each primitive block to determine whether one and the same inner logic state with abnormal IDDQ exists in the inner logic state with normal IDDQ or not. The former block is regarded as normal block and the latter block is regarded as faulty block. The fault of the faulty block can be localized easily by using input logic state simulation. Experimental results on real faulty LSI with 100k gates demonstrated rapid diagnosis times of within ten hours ani reliable extraction of the fault location.
Test and Failure Analysis Implications of a Novel Inter-Bit Dependency in a Non-Volatile Memory
Authors: Boyne D. , Goertz J. , Parsons D.
Published: December 2020

Failure analysis of non-volatile memory arrays can be complicated by the history of bits elsewhere in the array. This generally is in contrast to volatile memories, in which the state of all bits can quickly be reset by over-writing the bits, or by simply removing power from the array. On one of our products, EEPROM bits failed to program if certain patterns of bits were programmed elsewhere in the EEPROM array. During programming, high voltages (>18 volts) are present within the EEPROM array. Such voltage levels caused a narrow field oxide region to break down, thereby pulling down the programming voltage and preventing the successful programming of EEPROM transistors. What complicated the analysis, however, was that the breakdown only occurs if a checkerboard pattern is being programmed in one part of the array, while specific other EEPROM bits had previously been programmed elsewhere in the array. Until the failure mechanism was well understood, electrical screens were difficult to implement, because they typically do not account for complicated interactions between bits. This is especially true for nonvolatile memories, for which test time costs often prohibit the use of complicated test patterns with improved test coverage. This paper reviews the failure analysis, and proceeds to highlight the importance of knowing the contents of nonvolatile arrays prior to performing either failure analysis or automated testing on such an array. The case study therefore applies to both test and failure analysis engineers.
Thermal and Optical Enhancements to Liquid Crystal Hot Spot Detection Methods
Authors: Ferrier S.
Published: December 2020

Three enhancements to Liquid Crystal hot spot detection improve thermal and optical sensitivity while substantially maintaining simplicity, safety and relative low cost. These enhancements have permitted detection of hot spots unidentifiable by traditional LC methods. Details, capabilities and limitations of the enhancements are discussed, results of rudimentary defect thermal modeling are presented, and an improved metric for evaluating LC technique sensitivity is proposed.
The Identification of Thermal Fatigue Testing Method of Soldered Joints for Space Use
Authors: Yonemaru M. , Shimizu A. , Matsuda S. , Seo I.
Published: December 2020

Electronic devices have been used under various thermal conditions in space applications. The temperature range often exceeds 100°C, and the electronic devices are stressed by both high and low temperatures and thermal cycles. Since repairing and reworking of the spacecraft electronic hardware cannot be performed after launch, verifying the reliability of the hardware on the ground before the launch is essential. The thermal stresses to the electronic devices' soldered joints have recently tended to increase because the devices must be made smaller and lighter. The thermal fatigue of the soldered joints must be addressed in order to achieve highly reliable flight hardware. We studied a test method to estimate the thermal fatigue life of soldered joints for space use. This paper examines the thermal fatigue life using two kinds of test methods as heat-resistant evaluation tests of soldered joints for space use, and evaluates the effect of the test parameters on the thermal fatigue life of soldered joints. We conclude that the thermal fatigue life of soldered joints cannot be estimated accurately, if the test parameters are instituted uniformly.
Failure Analysis for Micro-Electrical-Mechanical Systems (MEMS)
Authors: Peterson K. A. , Tangyunyong P. , Barton D. L.
Published: December 2020

Micro-Electrical Mechanical Systems (MEMS) is an emerging technology with demonstrated potential for a wide range of applications including sensors and actuators for medical, industrial, consumer, military, automotive and instrumentation products. Failure analysis (FA) of MEMS is critically needed for the successful design, fabrication, performance analysis and reliability assurance of this new technology. Many devices have been examined using techniques developed for integrated circuit analysis, including optical inspection, scanning laser microscopy (SLM), scanning electron microscopy (SEM), focused ion beam (FIB) techniques, atomic force microscopy (AFM), infrared (lR) microscopy, light emission (LE) microscopy, acoustic microscopy and acoustic emission analysis. For example, the FIB was used to microsection microengines that developed poor performance characteristics. Subsequent SEM analysis clearly demonstrated the absence of wear on gear, hub, and pin joint bearing surfaces, contrary to expectations. Another example involved the use of infrared microscopy for thermal analysis of operating microengines. Hot spots were located, which did not involve the gear or hub, but indicated contact between comb structures which drive microengines. Voltage contrast imaging proved useful on static and operating MEMS in both the SEM and the FIB and identified electrostatic clamping as a potentially significant contributor to failure mechanisms in microengines. This work describes MEMS devices, FA techniques, failure modes, and examples of FA of MEMS.
Interpretation of Sudden Failures in Pump Laser Diodes
Authors: Bonfiglió A. , Vanzi M. , Casu M. B. , Magistrali F. , Maini M. , Salmini G.
Published: December 2020

The occurrence of sudden failures has been reported for 980 nm SL SQW InGaAs pump lasers. The post-mortem analysis reveals failure modes that are consistent with the formation of defects at the active area. The problem calls for two separate efforts: monitoring the degradation at suitable time resolution and structural characterization of defects. This article reports about the optical power and overall voltage monitoring results during a constant current lifetest, in which "sudden failures" switched off the lasers in a few hours, after 1500 hours of regular life, and about their interpretation based on TEM cross-sectional images across an EBIC-detected high recombination site. The hypothesis that Recombination Enhanced Defect Reaction (REDR) is a suitable mechanism for defect growth in forward biased GaAs-based diodes is proposed and discussed that REDR is the origin of the observed sudden failures, starting from native defects located in "cool" regions.
Laser Microchemical Technology: New Tools for Flip-Chip Debug and Failure Analysis
Authors: Silverman S. , Aucoin R. , Mallatt J. , Ehrlich D.
Published: December 2020

Laser microchemical (LMC) technology has become an important element of the FIA and debug tool set by supplying key steps not well addressed by previous tools. In this paper we report the optimization of the LMC technology to solve key issues for flip chip FIA. Specific processes have been developed for localized thinning of flip chips, in order to enable access of conventional FIA tools. Additional applications include dramatic enhancement of focused ion beam (FIB) rework and 3-D micromachining for prototyping, in-situ trimming, and mastering of microelectromechanical systems (MEMS). Laser etching of silicon is with a high pressure chlorine assist and is l000X the rate of the fastest focused ion beam methods. In contrast to grinding methods, the process introduces no process stress or contamination and retains an average surface roughness of several hundred angstroms. Micronthickness metal lines are laid down in a one-step vapor phase deposition at 200 μm/s writing speed. Rapid deposition combined with the superior quality of the laser interconnect, translates into writing with a conductance per unit writing time of 1000 to 10,000 times the rate of a focused ion beam.
Automatic Fault Tracing Using an E-Beam Tester with Reference to a Good Sample
Authors: Wada S.-I. , Nakamura T.
Published: December 2020

Locating fault origins of defective logic LSls requires expensive equipment, such as electron beam testers and LSI testers. In order to maximize the utilization of such equipment in achieving high fault analysis throughput as well as to save manpower, the authors are developing an automatic fault tracing system which locates the fault origin overnight without human assistance through control of an electron beam tester and an LSI tester. The system traces backwards via the fault propagation path and locates the fault origin by comparing the behavior of a faulty LSI sample with that of a good LSI sample. Sample exchange in a vacuum chamber is achieved through a dual chip loading mechanism. After initial setting, fault location is accomplished without human assistance by fully automated operations, such as fine tuning SEM images of LSI surfaces, aligning points by robust pattern matching between SEM images and layout data, acquiring voltage contrast images with high contrasts and judging logical voltage levels from the images. A prototype version of this system successfully backtraced to the fault origin of an LSI with 20 k gates in 8 hours.
The Business Aspects of Failure Analysis
Authors: Frank R. , Lee T.
Published: December 2020

This paper discusses the factors that determine the effectiveness of failure analysis (FA) and its impact on supply chain economics. It provides guidance and insight for users and suppliers on how to simplify and expedite the FA process, how to determine which failures to address, how requests should be prioritized, and how to set reasonable turnaround time objectives.
Failure Isolation of Mobile Ions Using Secondary Ion Mass Spectroscopy
Authors: John R.
Published: December 2020

Secondary Ion Mass Spectroscopy (SIMS) can be applied to all elements, and it facilitates the quantitative analysis of solid surfaces, including monolayers. The method is widely used in studies of adsorption, oxidation, corrosion, catalysis, diffusion and in characterization of thin films and coatings. [1] This technique can very well be applied in semiconductor failure analysis for not only detecting the source of failure, but also isolating the failure to a particular location, which is very important for corrective action procedures. SIMS analysis was performed on a CMOS VLSI sample with suspected mobile ionic problem, and it proved to be very effective in providing details of the specific mobile ionic elements involved, source of contamination, and resident location of the mobile ions.
Spin-On-Glass (SOG) Contamination Causing Single Via Failure
Authors: Isakanian P. , Hunjan S.
Published: December 2020

Several device failures were experienced after they went through the board assembly process. The failure caused severe transmit pulse attenuation from circuit block called AUI (Attachment Unit Interface). The AUI serves as a medium independent communication port in Local Area Networks. After careful observation and a series of Failure Analysis processes, the malfunction, which caused severe transmit pulse attenuation was attributed to a defective metal 1 to metal 2 via. The via in question is a tie between a pair of cascoded PMOS transistors in the analog section of the chip. These transistors serve as the main biasing leg for the AUI current sink. Since the via in question was bake recoverable at temperatures as low as 175°C for 20 minutes but would show the same failure signature when operated under temperature, the exact failure location was difficult to pinpoint. After a lengthy analysis procedure, the malfunction was attributed to contamination due to Spin On Glass (SOG) outgassing.
Use of Failure Analysis Techniques to Optimize the Passivation Process for a TLM 0.35 µm Process
Authors: Bothra S. , Sur H. , Brugge H. , Pramanik D.
Published: December 2020

Optimization of the passivation scheme for a 0.35 μm TLM process is presented. The passivation layer is required to provide mechanical and chemical protection during the assembly and packaging process and long term environmental protection. The passivation scheme was optimized by testing a product-like test vehicle at accelerated environmental stress conditions of high humidity and high temperature. The initial passivation scheme showed a unique electrical test signature - a voltage dependent failure with open circuit at low voltage/pass at high voltage. Advanced wafer-level failure analysis techniques and equipment were used to isolate and identify the failure site. Further cross-section analysis revealed that the failure site was a fracture across a via and adjoining IMO. This cracking was attributed to stress corrosion fracture of the IMO based on root cause analysis. This hypothesis required a path for moisture to the stressed IMO-2 location to cause the fracture. The moisture path was identified by further analysis and process changes to eliminate this were implemented. All subsequent parts passed the accelerated environmental tests confirming the stress corrosion fracture hypothesis.
Focused Ion Beam Application in Solving RFIC Oscillation Problem
Authors: Zhao S.P. , Ma H.N. , Fang S.J. , Goh G.P. , Wang J.
Published: December 2020

Focused Ion Beam (FIB) technique has been widely used to directly modify device functionality by adding ion-induced conductive lines and cutting signal traces with chemical enhance etching. However, in this work, FIB technique is employed to add a 15 ohm resistor to a RF circuit to solve its oscillation problem. After the modification, the oscillation problem is solved and the performance of the RF device is improved significantly. The successful FIB application of adding a defined resistor to modify a circuit is reported in this paper for the first time.
Preliminary Study of Alternative Material Development of Ballistic Attributes
Authors: Kim Dal Sun , Nemat-Nasser Sia. , Seon Kim Yun
Published: December 2020

The purpose of this research is to examine the performance of tungsten heavy alloy (WHA) susceptible to adiabatic shear failures and to identify the microscopic findings of shear band and its effect on the engineering behavior. Experimental results show that the binder-phase (Fe-Ni) and tungsten particles (W) have the high work-hardening rate at low-strain-rate compression (10-3/sec). Thermal softening behavior is dominant at high-strain-rate (>103/sec), and this material is relatively insensitive to strain rate in the range of 3000-5000/sec. The microscopic analysis by SEM reveals that most fractures in the shear band are intergranular where the Fe-Ni matrix has the least resistance to fracture. Transgranular fracture is also observed, but not significantly. With the constant strain rate, no shear band was observed under 30% compressive strain, whereas the extensive shear band was formed at the 50% strain with significant crack formation along the shear band zone and extends through the specimen thickness forming a cone shape inclined at an angle 40° to 50° to the loading direction. The measured surface temperature of the 40%-strained specimen is approximately 250 °C using high speed infrared temperature technique. A significant decrease in the ultrasonic velocities is measured with extension of the shear band.
Effects of Prior Processing on the Performance of PH 13-8 Mo Stainless Steel
Authors: Pepi Marc S. , Grendahl Scott M.
Published: December 2020

This article deals with an investigation to determine the root cause of the differences noted in the fatigue test data of main rotor spindle assembly retaining rods fabricated from three different materials. The US Army Research Laboratory - Materials Directorate (ARL) subjected the failed tie rods to visual examination and light optical microscopy and then performed dimensional verification and measured the respective surface roughness of the rods in an effort to identify any discrepancies. Next, mechanical testing (hardness, fatigue, and tensile) was performed, followed by metallography, and chemical analysis. Finally, the ARL performed laboratory heat treatments at the required aging temperature. The results suggested that the difference in performance could not be directly linked to chemical composition, dimensional intolerance, surface roughness or any metallographic variance and that the likely explanation for the difference observed in the mechanical performance of materials lies within a variation of the heat treatment.
In-Situ Electrical Monitoring and Contactless Measurement Techniques for Enhanced FIB Modifications
Authors: Desplats Romain , Benbrik Jamel , Perdu Philippe , Benteo Bruno , Marc François , Danto Yves
Published: December 2020

Recent planar technologies with 3 metal layers or more challenge current physical design modification capacities using Focused Ion Beam tools. Image visibility on the FIB is drastically reduced, making accurate positioning and milling operations in the area of interest more difficult, and the use of power planes increases the risk of short circuits while accessing inferior metal lines. Despite the complexity of FIB modifications, however, the demand for circuit modifications continues to increase. To respond to this demand for successful, time efficient, FIB modifications, step by step monitoring of operations is imperative. In this paper, we will present an innovative method which brings in-situ electrical monitoring and contactless measurement capabilities to FIB systems. Electrical connection of the circuit inside the vacuum FIB chamber is done using a commercial load module and logic waveform acquisition with the FIB is obtained without modifying FIB hardware using a voltage contrast approach. With this method, it is possible to verify the completion of FIB milling and depositing operations by temporarily suspending FIB action so that a test pattern can be run allowing electrical testing and measurements of the circuit without damaging it.
ESD Induced Failures in Cermet Trim Potentiometers
Authors: Ebel George H.
Published: December 2020

Production had been halted on an electronic system due to sudden and unexplainable shifts in the resistance values of some Cermet poteniometers. This paper describes the method used to confirm that the problem was due to an ESD environment.
Graphical Representation of Permanent Defects in Hard Disk Drives
Authors: Mohr Josef , Agness John
Published: December 2020

This paper discusses the utilization of a specifically designed magnetic media defect plotting utility. This utility provides the analyst with the ability to view the physical locations of data errors on the disk drive and identify damage to magnetic media. With the failure signature understood, the analyst can now go on to isolate the underlying failure mechanism, without electrical analysis. Further, with the failure mechanism identified critical feedback can be provided to appropriate engineering areas so that the cause of failure can be limited at its source.
Evaluation of the Resistance of Individual Si Die to Cracking
Authors: Berriche R. , Lowry R.K. , Rosenfield M.I.
Published: December 2020

The present work investigated the use of the Vickers micro-hardness test method to determine the resistance of individual die to cracking. The results are used as an indicator of resistance to failure under the thermal and mechanical stresses of packaging and subsequent thermal cycling. Indentation measurements on die back surfaces are used to determine how changes in wafer backside processing conditions affect cracks that form around impressions produced at different loads. Test methodology and results obtained at different processing conditions are discussed.
Electromigration in Gold Line of GaAs IC
Authors: Ohta A. , Yajima K. , Higashisaka N. , Heima T. , Hisaka T. , Tanino N.
Published: December 2020

This paper describes voids in a gold line, which is a new failure mechanisms of GaAs IC using gold line as interconnection. We have found voids in both first and second metal under DC bias test, current density of 0.67 to 1.27 106 A/cm2 in high temperature range of 230 °C to 260 °C. We have observed carefully the movement of voids during the test and found that voids moved toward a cathode, in the opposite direction of electron flow. The velocity of voids increased with the current density almost proportionally. The moving mechanisms of a void can be explained by assuming that gold atoms move toward an anode by electromigration. The activation energy of the void velocity was 0.84 eV at the cathode side. This was nearly equal to 0.6 eV - 0.9 eV reported on the velocity of the gold island on molybdenum surfaces [1]. The GaAs IC failed at the almost same time as the voids appeared. The activation energy of mean time to failure of the IC was 0.89 eV, which was nearly equal to that of the void velocity at the cathode edge of 0.84 eV.
Simple Flip Chip Analysis Strategies
Authors: Tubbs Richard L.
Published: December 2020

Recent customer demands and advances in technology are expanding the use of flip chip ICs. The higher coefficients of thermal expansion differences and fragile nature of assemblies have made underfilling mandatory for product survival in the field. This article describes a few techniques employed for failure analysis of these complex devices: epoxy development, substrate pre-encapsulation, universal polishing media, cyanoacrylate use, substrate analysis, plan view sectioning/inspection, die backside polishing for infra-red inspection, and chemical deprocessing. Almost all of the techniques presented will involve traditional cross sectioning tools which can be applied to flip chips. These techniques include improvements to the traditional material analysis cross section as well as aids for die level electrical analysis and visual inspection methods. The article demonstrates that with the use of the described techniques, and literally no investment, any lab which can presently perform semiconductor related cross-sections, will be able to confidently expand into flip chips.
Making the Most of the Internet for Failure Analysis
Authors: Bodoh Dan J.
Published: December 2020

The growth of the Internet over the past four years provides the failure analyst with a new media for communicating his results. The new digital media offers significant advantages over analog publication of results. Digital production, distribution and storage of failure analysis results reduces copying costs and paper storage, and enhances the ability to search through old analyses. When published digitally, results reach the customer within minutes of finishing the report. Furthermore, images on the computer screen can be of significantly higher quality than images reproduced on paper. The advantages of the digital medium come at a price, however. Research has shown that employees can become less productive when replacing their analog methodologies with digital methodologies. Today's feature-filled software encourages "futzing," one cause of the productivity reduction. In addition, the quality of the images and ability to search the text can be compromised if the software or the analyst does not understand this digital medium. This paper describes a system that offers complete digital production, distribution and storage of failure analysis reports on the Internet. By design, this system reduces the futzing factor, enhances the ability to search the reports, and optimizes images for display on computer monitors. Because photographic images are so important to failure analysis, some digital image optimization theory is reviewed.
ESD Protection Using Active Area Bonding
Authors: Bernier Joe C. , Teems Larry
Published: December 2020

In the never ending battle for smaller, faster, cheaper semiconductors, ESD protection is more and more becoming a driving factor. Since scaling the ESD protection devices usually means scaling the level of protection as well, methods for providing good ESD robustness in less real estate are required. By placing some ESD circuitry under the bond pads and maintaining good control over the wire bond process, good ESD levels can be obtained, excellent reliability can be achieved and significant die area can be saved.
The Effect of Ball Pad Metallurgy and Ball Composition on Solder Ball Integrity of Plastic Ball Grid Array Packages
Authors: Zhong C.H. , Yi Sung
Published: December 2020

Ball shear forces of plastic ball grid array (PBGA) packages are found to decrease after reliability test. Packages with different ball pad metallurgy form different intermetallic compounds (IMC) thus ball shear forces and failure modes are different. The characteristic and dynamic process of IMC formed are decided by ball pad metallurgy which includes Ni barrier layer and Au layer thickness. Solder ball composition also affects IMC formation dynamic process. There is basically no difference in ball shear force and failure mode for packages with different under ball pad metallurgy before reliability test. However shear force decreased and failure mode changed after reliability test, especially when packages exposed to high temperature. Major difference in ball shear force and failure mode was found for ball pad metallurgy of Ni barrier layer including Ni-P, pure Ni and Ni-Co. Solder ball composition was found to affect the IMC formation rate.
Failure Analysis of Advanced Microprocessors through Backside Approaches
Authors: Davis D. , Diaz de Leon O. , Hughes L. , Pabbisetty S. V. , Parker R. , Scott P. , Todd C. , Widaski J. , Wilhite G. , Wills K.S. , Zhu J.
Published: December 2020

The advent of Flip Chip and other complex package configurations and process technologies have made conventional failure analysis techniques inapplicable. This paper covers the ways in which conventional techniques have been modified to meet the FA challenges presented by these new devices – specifically, by forcing analysis to be done from the backside of the device. Modifications to the traditional FA process steps, including new sample preparation methods, changes in hardware, and alterations to physical failure analysis processes are described. To demonstrate the use of backside analytical approaches, some examples of applications and a case study are also included.
Terahertz Imaging: A New Technique for Inspection of Dielectric Materials
Authors: Mittleman Daniel M.
Published: December 2020

Terahertz time-domain spectroscopy (THz-TDS) is a promising new technology which provides a relatively simple means of generating and detecting single-cycle pulses of far-infrared (or terahertz) radiation. One of the most interesting aspects of this system is its insensitivity to the thermal background. This obviates the need for cryogenic apparatus; as a result, this may be the first portable far-infrared spectrometer. Recent work has demonstrated the possibility of tomographic imaging using THz-TDS. In this imaging mode, a reflected pulse train is used to construct a three-dimensional representation of a composite material, using the timing between reflected pulses to determine the spacing between adjacent dielectric interfaces. Here, the transverse resolution is determined by the diffraction-limited focus of the THz beam, and is typically ~300 microns. The longitudinal (depth) resolution of ~100 microns is determined by the coherence length of the radiation, although the location of isolated surfaces can be determined with far higher precision. Since many common packaging materials have high transparency in the THz range, this suggests the possibility of exploiting this new imaging system for non-invasive testing and on-line monitoring. The operation of the THz “T-ray” imaging system will be described, and several examples will be provided which illustrate its capabilities and limitations.
Temperature Profile Measurement and Failure Characterization of ESD Protection Devices Using Spectroscopic Photon Emission Microscopy and Raman Spectroscopy
Authors: Rasras Mahmoud , De Wolf Ingrid , Groeseneken Guido , Chen Jian , Bock Karlheinz , Maes Herman E.
Published: December 2020

In this paper, Photon Emission Microscopy (PEM) and micro-Raman Spectroscopy (μRS) are applied for temperature profile measurements and failure characterization in gg-nMOS ESD protection devices. The measurements were carried out in avalanche and snapback biasing conditions. A correlation between the temperature profile obtained by μRS and the light emission location, measured by PEM, is observed for non-degraded devices. In addition, ESD-degraded devices were studied. PEM, μRS, Spectroscopic Photon Emission Microscopy (SPEM) and electrical measurements were used to investigate the origin of the light emitted at the failure site. They showed that the light emission occurring at the failure site is due to impact ionization.
Automatic TEM Sample Preparation
Authors: Kaplan Wayne D. , Kisslinger Kim , Oviedo Ron , Raz Efrat M. , Smith Colin
Published: December 2020

The rising demand in the semiconductor industry for higher spatial resolution in the analysis of device defects has focused attention on the use of transmission electron microscopy (TEM). However, conventional TEM sample preparation may be difficult and time-consuming, and depending on the operator may result in a low yield of quality specimens. One solution to this problem is the use of focused ion beam (FIB) milling for the final stage of TEM sample preparation. However, specimens have to be mechanically thinned prior to FIB processing, and the need to characterize specific devices requires a pre-FIB preparation method to isolate specific regions on the wafer. An innovative and automated solution that isolates specific devices and prepares TEM specimens for subsequent thinning by FIB has been developed. Based on controlled microcleaving technology, the system automatically performs the pre-FIB preparation in less than 30 minutes. An important added benefit is that the target area to be analyzed can be positioned at a specific distance from the sample edge, thereby facilitating the final FIB milling stage. The thinned specimen is automatically packaged for subsequent FIB processing and TEM. Details of the method and examples showing TEM results from tungsten filled vias are presented.
A Technique for Measuring Device Temperature with High Accuracy in Accelerated Operational Life Tests
Authors: Takeda K. , Harigaya M. , Miyazaki Y.
Published: December 2020

This paper describes a new technique for measuring junction temperature with high accuracy in accelerated operational tests (junction temperature ≥200°C) based on the measurements of temperature dependence of gate-leakage current on a GaAs FET (gate-leakage method). The gate-leakage current on the GaAs FET is monitored in the accelerated operational tests. Then, junction temperature and thermal resistance are calculated from the temperature dependence of the gate-leakage current, especially from the temperature dependence in high temperature region. We have measured the junction temperature and the thermal resistance using this method in accelerated operational tests, and have confirmed that the junction temperature can be estimated within a range of ten degrees. The results by this method have been compared with data of simulation, and the validity has been confirmed.
Modeling and Optimizing XeF2-enhanced FIB Milling of Silicon
Authors: Bassom Neil J. , Mai Tung
Published: December 2020

Wide variations in the dose enhancement factor observed when milling silicon using Focused Ion Beam (FIB) XeF2 Gas Assisted Etching (GAE) prompted the development of a simple model of the GAE process. The model accounts for three material removal mechanisms: regular sputtering; gas-assisted sputtering; and spontaneous chemical reactions. An expression linking the dose enhancement factor, εd, to the gas and milling parameters has been derived. Experiments show that εd behaves as predicted; good quantitative agreement is achieved over wide ranges of milling parameters for εd values between 20X and 2500X. Conditions required to minimize variations in d and maximize material removal rates, M, are derived. It is shown that if the dose per unit area per raster is below a threshold value then εd and M depend only on the average current density J (the area of the box divided by the beam current). A consideration of the J regimes used for front-side and back-side FIB work shows why changes in εd have not previously been a problem but are inevitable when milling the large trenches characteristics of Flip Chip circuit modification work. While εd changes dramatically there is a region of J values for which M is approximately constant.
In-Situ Dual Beam (FIBSEM) Techniques for Probe Pad Deposition and Dielectric Integrity Inspection in 0.2 μm Technology DRAM Single Cells
Authors: Zimmermann Gunnar , Chapman Richard
Published: December 2020

Dual beam FIBSEM systems invite the use of innovative techniques to localize IC fails both electrically and physically. For electrical localization, we present a quick and reliable in-situ FIBSEM technique to deposit probe pads with very low parasitic leakage (Ipara < 4E-11A at 3V). The probe pads were Pt, deposited with ion beam assistance, on top of highly insulating SiOx, deposited with electron beam assistance. The buried plate (n-Band), p-well, wordline and bitline of a failing and a good 0.2 μm technology DRAM single cell were contacted. Both cells shared the same wordline for direct comparison of cell characteristics. Through this technique we electrically isolated the fail to a single cell by detecting leakage between the polysilicon wordline gate and the cell diffusion. For physical localization, we present a completely in-situ FIBSEM technique that combines ion milling, XeF2 staining and SEM imaging. With this technique, the electrically isolated fail was found to be a hole in the gate oxide at the bad cell.
FIB Micromachining and Nano-Structure Fabrication
Authors: Lee Raymond A. , Wolpert Patrick J.
Published: December 2020

FIB Micromachining has long been an established technique, but until recently it has been overshadowed by the more mainstream semiconductor application of the Focused Ion Beam system. Nano- Structure fabrication using the FIB system has become more popular recently due to several factors. The need for sub-micron structures have grown significantly due to a need for enhanced optical and biological applications. Another reason for the growth in micromachining is the improvement made in the ability of FIB systems to produce geometric shapes with high precision. With the latest high-end FIB systems, it is possible to produce microstructures with tens of nano-meters of precision. Optical lens, AFM tips, and nano-apertures are all part of the growing application for FIB Micromachining. This paper will discuss the ability and limitations of the FIB system and some possible application for FIB Micromachining.
Investigation of High Frequency Failures on a 0.35μm CMOS IC
Authors: Kennen Alan , Guravage John F. , Foster Lauren , Kornblum John
Published: December 2020

Rapidly changing technology highlights the necessity of developing new failure analysis methodologies. This paper will discuss the combination of two techniques, Design for Test (DFT) and Focused Ion Beam (FIB) analysis, as a means for successfully isolating and identifying a series of high impedance failure sites in a 0.35 μm CMOS design. Although DFT was designed for production testing, the failure mechanism discussed in this paper may not have been isolated without this technique. The device of interest is a mixed signal integrated circuit that provides a digital up-convert function and quadrature modulation. The majority of the circuit functions are digital and as such the majority of the die area is digital. For this analysis, Built In Self Test (BIST) circuitry, an evaluation board for bench testing and FIB techniques were used to successfully identify an unusual failure mechanism. Samples were subjected to Highly Accelerated Stress Test (HAST) as part of the device qualification effort. Post-HAST electrical testing at 200MHz indicated that two units were non-functional. Several different functional blocks on the chip failed electrical testing. One part of the circuitry that failed was the serial interface. The failure analysis team decided to look at the serial interface failure mode first because of the simplicity of the test. After thorough analysis the FA team discovered increasing the data setup time at the serial port input allowed the device to work properly. SEM and FIB techniques were performed which identified a high impedance connection between a metal layer and the underlying via layer. The circuit was modified using a FIB edit, after which all vectors were read back correctly, without the additional set-up time.
Recent Advances in Broad Ion Beam Based Techniques/Instrumentation for SEM Specimen Preparation of Semiconductors
Authors: Alani R. , Mitro R. J. , Hauffe W.
Published: December 2020

The semiconductor industry routinely prepares crosssectional SEM specimens using several traditional techniques. Included in these are cleaving, mechanical polishing, wet chemical etching and focused ion beam (FIB) milling. This presentation deals with a new alternate method for preparation of SEM semiconductor specimens based upon a dedicated broad ion beam instrument. Offered initially as an alternative to wet chemical etching, the instrument was designed to etch and coat SEM and metallographic specimens in one vacuum chamber using inert gas (Ar) ion beams. The system has recently undergone further enhancement by introducing iodine Reactive Ion Beam Etching (RIBE) producing much improved etching/cleaning capabilities compared with inert gas ion beam etching. Further results indicate Ar broad ion beam etching can offer a rapid, simple, more affordable alternative (to FIB machines) for precision cross sections and for “slope cutting,” a technique producing large cross-sections within a short time frame. The overall effectiveness of this system for iodine RIBE etching, for precision cross sectioning and “slope cutting” will be shown for a number of traditional and advanced semiconductor devices.
X-Ray Tomography for Electronic Packages
Authors: Goyal Deepak
Published: December 2020

Next generation assembly/package development challenges are primarily increased interconnect complexity and density with ever shorter development time. The results of this trend present some distinct challenges for the analytical tools/techniques to support this technical roadmap. The key challenge in the analytical tools/techniques is the development of non-destructive imaging for improved time to information. This paper will present the key drivers for the non-destructive imaging, results of literature search and evaluation of key analytical techniques currently available. Based on these studies requirements of a 3D imaging capability will be discussed. Critical breakthroughs required for development of such a capability are also summarized.