Reliability of silver wedge bonding for power devices

2015 ◽  
Vol 2015 (1) ◽  
pp. 000735-000739
Author(s):  
Xing Wei ◽  
Zhou Yu ◽  
Wanmeng Xu ◽  
Tomonori Iizuka ◽  
Kohei Tatsumi
Keyword(s):  
Intermetallic Compounds ◽  
Power Loss ◽  
Corrosion Layer ◽  
Energy Dispersive ◽  
Power Devices ◽  
X Ray ◽  
Higher Temperature ◽  
Ic Package ◽  
Wedge Bonding

Recently there is a trend toward to use SiC instead of Si in power devices since SiC can withstand higher temperature (above 300°C) and higher voltage with less power loss than Si. So there is a great interest to improve interconnection technique for power devices package. In this study, Ag wire with diameter of 200 μm was bonded on Al pad, after annealing at 200°C and 300°C, intermetallic compounds (IMC) were investigated by energy dispersive X-ray spectroscopy (EDS). The results show that, when annealed in air, two kinds of IMC Ag2Al and Ag3 Al formed and no voids or cracks were observed; but when annealed with epoxy molded IC package, voids were observed, and between Ag wire and IMC there was a corrosion layer.

Determination of Orientation Relationship between TiC and Ti2CS in a Ti-Containing Steel by TEM

2013 ◽  
Vol 331 ◽  
pp. 531-535
Author(s):  
Qing Hong Luo ◽  
De Lu Liu ◽  
Chun Zhi Li
Keyword(s):  
Titanium Carbide ◽  
Epitaxial Growth ◽  
Orientation Relationship ◽  
Energy Dispersive Spectrum ◽  
Energy Dispersive ◽  
X Ray ◽  
Higher Temperature ◽  
Weathering Resistance

The orientation relationship between TiC and Ti2CS in a Ti-containing weathering-resistance steel were observed by TEM technology and X-ray energy dispersive spectrum (EDS). The results showed that many tiny TiC (titanium carbide) were forming on Ti2CS (titanium carbide sulfide), which precipitates on relatively higher temperature than TiC, The orientation relationship between TiC and Ti2CS is ; . The epitaxial growth is important mechanisms for titanium carbide forming in steels.

The reliability of Ag wedge bonding with various bonding pads for power devices

2016 ◽  
Vol 2016 (1) ◽  
pp. 000385-000389
Author(s):  
Xing Wei ◽  
Zhou Yu ◽  
Ge Yan ◽  
Tomonori Iizuka ◽  
Kohei Tatsumi
Keyword(s):  
Shear Strength ◽  
High Temperature ◽  
Intelligent Vehicles ◽  
Power Devices ◽  
Bonding Wire ◽  
Parasitic Parameters ◽  
Higher Temperature ◽  
Wedge Bonding ◽  
Device Size ◽  
Temperature Storage

Abstract Recent years, with the development of intelligent vehicles, power devices would be widely used. But traditional Si power devices have problems under high temperature. Now, there is a tendency that using SiC instead of Si in power devices, as SiC has a higher band gap 3.25 eV comparing with 1.12 eV of Si. So that SiC power devices can withstand higher temperature and voltage. Also SiC power devices have the advantages of lower parasitic parameters, smaller device size and shorter response time. In this study, to investigate the reliability of Ag wedge bonding, Ag wires were bonded on Al pad and Au-Ni pad. And then we did shear test after high temperature storage life test (HTSL). Finally, we used energy dispersive X-ray spectroscopy (EDS) to do cross-section observation. The results show that, for Al pad, the shear strength has decreased after annealing at 300°C with mold packages, cracks and corrosion were observed. For Au-Ni pad, the shear strength has increased after annealing, and no cracks or corrosion formed. So Ag bonding wire is proposed as an alternative to Al bonding wire for selected metal pads in power devices.

scholarly journals Characterizing Atomic Ordering in Intermetallic Compounds Using X-ray Energy Dispersive Spectroscopy in an Aberration-Corrected (S)TEM

2016 ◽  
Vol 22 (S3) ◽  
pp. 1266-1267
Author(s):  
Robert Williams ◽  
Anna Carlsson ◽  
Arda Genҫ ◽  
John Sosa ◽  
David McComb ◽  
...  
Keyword(s):  
Intermetallic Compounds ◽  
Energy Dispersive Spectroscopy ◽  
Energy Dispersive ◽  
Atomic Ordering ◽  
X Ray ◽  
Aberration Corrected

Structural evolution of aqueous mercury sulphide precipitates: energy-dispersive X-ray diffraction studies

2010 ◽  
Vol 74 (1) ◽  
pp. 85-96 ◽  
Author(s):  
A. M. T. Bell ◽  
R. A. D. Pattrick ◽  
D. J. Vaughan
Keyword(s):  
High Temperature ◽  
Structural Evolution ◽  
Phase Changes ◽  
Energy Dispersive ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Synthetic Sample ◽  
X Ray ◽  
Higher Temperature ◽  
Aqueous Mercury

AbstractIn situ, high-temperature energy-dispersive X-ray powder diffraction (EDXRD) data have been collected on synthetic and a natural sample of mercury sulphide (HgS). These measurements were made between temperatures of 295 and 798 K. Synthetic samples of HgS were prepared by reaction between sulphide and mercury in aqueous solution. In a subsequently dried and aged synthetic HgS sample, heated in vacuo, there is a change from a poorly crystalline pseudocubic material into a well crystalline cubic material in the temperature region 583–623 K. At higher temperature (748 K), there is evidence for a partial phase transition to the high temperature hypercinnabar HgS structure. In a neoformed synthetic sample, heated in a sealed Ti container, the initial ‘pseudocubic’ metacinnabar phase partially transforms to a previously unknown phase (XHgS) in the temperature range 467–522 K. This phase disappears at 527 K, and the metacinnabar phase changes to a well crystalline cubic phase; cinnabar develops at 542 K. The proportion of cinnabar continues to increase up to 647 K. Both metacinnabar and cinnabar phases are retained on cooling. No phase transitions were observed for the natural cinnabar sample.

Quantitative Electron-Excited X-ray Microanalysis With Low-Energy L-shell X-ray Peaks Measured With Energy-Dispersive Spectrometry

2021 ◽  
pp. 1-34
Author(s):  
Dale E. Newbury ◽  
Nicholas W.M. Ritchie
Keyword(s):  
Intermetallic Compounds ◽  
Photon Energy ◽  
Matrix Effects ◽  
Energy Dispersive ◽  
Extensive Experience ◽  
X Ray ◽  
Rigorous Testing ◽  
Accuracy Of Measurements ◽  
Wide Range ◽  
Analytical Accuracy

Quantification of electron-exited X-ray spectra following the standards-based “k-ratio” (unknown/standard intensity) protocol with corrections for “matrix effects” (electron energy loss and backscattering, X-ray absorption, and secondary X-ray fluorescence) is a well-established method with a record of rigorous testing and extensive experience. Two recent studies by Gopon et al. working in the Fe–Si system and Llovet et al. working in the Ni–Si system have renewed interest in studying the accuracy of measurements made using L-shell X-ray peaks. Both have reported unexpectedly large deviations in analytical accuracy when analyzing intermetallic compounds when using the low photon energy Fe or Ni L-shell X-ray peaks with pure element standards and wavelength-dispersive X-ray spectrometry. This study confirms those observations on the Ni-based intermetallic compounds using energy-dispersive X-ray spectrometry and extends the study of analysis with low photon energy L-shell peaks to a wide range of elements, Ti to Se. Within this range of elements, anomalies in analytical accuracy have been found for Fe, Co, and Ge in addition to Ni. For these elements, the use of compound standards instead of pure elements usually resulted in significantly improved analytical accuracy. However, compound standards do not always provide satisfactory accuracy as is demonstrated for L-shell peak analysis in the Fe–S system: FeS and FeS2 unexpectedly do not provide good accuracy when used as mutual standards.

High Temperature Resistant Packaging for SiC Power Devices Using Interconnections Formed by Ni Micro-Electroplating

2014 ◽  
Vol 778-780 ◽  
pp. 1110-1113 ◽  
Author(s):  
Noriyuki Kato ◽  
Akiyoshi Shigenaga ◽  
Kohei Tatsumi
Keyword(s):  
High Temperature ◽  
Electrical Properties ◽  
Power Loss ◽  
Power Devices ◽  
Control Units ◽  
Compact Size ◽  
Higher Power ◽  
Nickel Electroplating ◽  
Higher Temperature ◽  
Die Bonding

High temperature SiC devices require the materials for packaging also capable of working at higher temperature than those for Si devices. SiC devices are expected to help hybrid vehicle power control units (PCUs) produce higher power in a more compact size as SiC can withstand higher voltages and temperatures (above 300°C) than silicon with less power loss. The improvement of interconnection technologies is increasingly becoming a top priority, particularly for the operation of SiC devices at relatively high temperatures. We propose a new interconnection method using nickel electroplating to replace Al wire bonding or die-bonding using solder materials. During the evaluation of the reliability of interconnections annealed at up to 500°C, we observed no significant changes in mechanical or electrical properties. We found that micro-plating connections can be used successfully for high-temperature-resistant packaging for SiC devices.

Microanalysis of precipitates in a ferritic steel

1978 ◽  
Vol 36 (1) ◽  
pp. 618-619
Author(s):  
J.M. Titchmarsh
Keyword(s):  
Ferritic Steel ◽  
Particle Identification ◽  
Energy Dispersive ◽  
Objective Lens ◽  
Ferritic Steels ◽  
Replica Technique ◽  
X Ray ◽  
Large Numbers ◽  
Scanning Transmission ◽  
Made In

The advances in recent years in the microanalytical capabilities of conventional TEM's fitted with probe forming lenses allow much more detailed investigations to be made of the microstructures of complex alloys, such as ferritic steels, than have been possible previously. In particular, the identification of individual precipitate particles with dimensions of a few tens of nanometers in alloys containing high densities of several chemically and crystallographically different precipitate types is feasible. The aim of the investigation described in this paper was to establish a method which allowed individual particle identification to be made in a few seconds so that large numbers of particles could be examined in a few hours.A Philips EM400 microscope, fitted with the scanning transmission (STEM) objective lens pole-pieces and an EDAX energy dispersive X-ray analyser, was used at 120 kV with a thermal W hairpin filament. The precipitates examined were extracted using a standard C replica technique from specimens of a 2¼Cr-lMo ferritic steel in a quenched and tempered condition.

Energy Dispersive X-Ray Measurements of thin Metal Foils

1976 ◽  
Vol 34 ◽  
pp. 426-427
Author(s):  
J. Bentley ◽  
E. A. Kenik
Keyword(s):  
Materials Science ◽  
Energy Dispersive Spectrometer ◽  
Thin Foil ◽  
Thin Metal ◽  
Energy Dispersive ◽  
Thin Specimen ◽  
X Ray ◽  
Metal Foils ◽  
Small Probe ◽  
Scanning Transmission

Instruments combining a 100 kV transmission electron microscope (TEM) with scanning transmission (STEM), secondary electron (SEM) and x-ray energy dispersive spectrometer (EDS) attachments to give analytical capabilities are becoming increasingly available and useful. Some typical applications in the field of materials science which make use of the small probe size and thin specimen geometry are the chemical analysis of small precipitates contained within a thin foil and the measurement of chemical concentration profiles near microstructural features such as grain boundaries, point defect clusters, dislocations, or precipitates. Quantitative x-ray analysis of bulk samples using EDS on a conventional SEM is reasonably well established, but much less work has been performed on thin metal foils using the higher accelerating voltages available in TEM based instruments.

Preparation And elemental analysis of ancient fibers

1987 ◽  
Vol 45 ◽  
pp. 410-411
Author(s):  
Allen Angel ◽  
Kathryn A. Jakes
Keyword(s):  
Cross Sections ◽  
Physical Structure ◽  
Energy Dispersive ◽  
Archaeological Sites ◽  
X Ray ◽  
Long Term Storage ◽  
Backscattered Electron ◽  
Electron Imaging

Fabrics recovered from archaeological sites often are so badly degraded that fiber identification based on physical morphology is difficult. Although diagenetic changes may be viewed as destructive to factors necessary for the discernment of fiber information, changes occurring during any stage of a fiber's lifetime leave a record within the fiber's chemical and physical structure. These alterations may offer valuable clues to understanding the conditions of the fiber's growth, fiber preparation and fabric processing technology and conditions of burial or long term storage (1).Energy dispersive spectrometry has been reported to be suitable for determination of mordant treatment on historic fibers (2,3) and has been used to characterize metal wrapping of combination yarns (4,5). In this study, a technique is developed which provides fractured cross sections of fibers for x-ray analysis and elemental mapping. In addition, backscattered electron imaging (BSI) and energy dispersive x-ray microanalysis (EDS) are utilized to correlate elements to their distribution in fibers.

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