scholarly journals Effect of Temperature on the Chip Soldering Process with AuGa0.03 Alloy Solder

Crystals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 59 ◽  
Author(s):  
Zhihuan Zhao ◽  
Guanghao Gong ◽  
Mingming Jiang ◽  
Chuanzhong Chen ◽  
Yingyue Pan ◽  
...  
Keyword(s):  
Cross Sections ◽  
Eutectic Reaction ◽  
Eutectic Structure ◽  
Effect Of Temperature ◽  
Sem Images ◽  
Soldering Temperature ◽  
Soldering Process ◽  
Xrd Diffraction ◽  
Alloy Solder ◽  
Negative Impacts

In this study, soldering is conducted between a chip and a CLCC-3 shell base with a sheet-like AuGa0.03 alloy solder as the encapsulating material. X-ray images of chip soldering samples, XRD diffraction analysis of the joints, SEM images reflecting the microstructures of the joints, and EDS of the cross sections of the chip soldering samples show that with gradually increasing soldering temperature, the phase composition is not affected, and all the joint structures are an Au + Si eutectic structure; the Au–Si eutectic reaction occurs during the soldering process. No deposition of meta-stable phases, such as Au7Si, Au5Si, or Au3S, is found. A soldering temperature of 420 °C can reduce the negative impacts of secondary cap welding soldering on the joint and improve the structure and mechanical properties of the joint.

Gymnomitrion fissum (Gymnomitriaceae, Marchantiophyta) — a new species with fissured leaf surface from China

2017 ◽  
Vol 51 ◽  
pp. 274-280
Author(s):  
A. D. Potemkin ◽  
Yu. S. Mamontov ◽  
N. S. Gamova
Keyword(s):  
New Species ◽  
Cross Sections ◽  
Cell Walls ◽  
Leaf Surface ◽  
Outer Cell ◽  
Sem Images ◽  
Cell Lumen ◽  
A New Species ◽  
Surface Comparison

Study of selected specimens of Gymnomitrion collected by D. G. Long in Yunnan, China, revealed a new species, G. fissum Mamontov et Potemkin, sp. nov., with a fissured leaf surface. Comparison of SEM images of the leaf surface and leaf cross sections shows that the leaf surface of G. fissum is different from that of other known species with a superficially similar leaf surface, i. e. Mylia taylorii, M. verrucosa s. l. and Trabacellula tumidula. It has fissures around the cell lumen rather than grids and perforations. Outer cell walls of Gymnomitrion fissum are much thicker than in Mylia taylorii, M. verrucosa s. l. and Trabacellula tumidula, and their outer layers tend to be partly or completely caducous. G. fissum is related to the group of species assigned to the former genus Apomarsupella.

scholarly journals In Situ Delineation Etch Reveals Subtle Detail in SEM Images of Ion Milled Cross Sections Enabling In-Fab 3-D Metrology and Characterization

2000 ◽  
Vol 8 (2) ◽  
pp. 36-39
Author(s):  
Clive Chandler
Keyword(s):  
Sample Preparation ◽  
Cross Sections ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Automated System ◽  
Sem Images ◽  
Difficult Time ◽  
Device Structures ◽  
Wet Etch ◽  
Conventional Sample

Control of layer thickness is critically important in the manufacture of semiconductor devices. Cross-sectioning exposes device structures for direct examination but conventional sample preparation procedures are difficult, time consuming, and grossly destructive. Cross sections created by focused ion beam (FIB) milling are easier, faster, and less destructive but have not offered the clear layer delineation provided by etching in the conventional sample preparation process. A new gas etch capability (Delineation Etch™ from FEI Company) offers results that are equivalent to conventional wet-etch preparations in a fraction of the time from a single, automated system in the fab without destroying the wafer. The new etch process also has application in milling high-aspect-ratio holes to create contacts to buried metal layers, and in deprocessing devices to reveal silicon and polysilicon structures.

scholarly journals Effect of adding TiO2 nanoparticles on the SEM morphology and mechanical properties of conventional heat-cured acrylic resin

2019 ◽  
Vol 13 (3) ◽  
pp. 234-240
Author(s):  
Elnaz Moslehifard ◽  
Mahmood Robati Anaraki ◽  
Saeed Shirkavand
Keyword(s):  
Impact Strength ◽  
Tio2 Nanoparticles ◽  
Cross Sections ◽  
Average Particle Size ◽  
Acrylic Resin ◽  
Mechanical Tests ◽  
Average Particle ◽  
Sem Images ◽  
Tio2 Nps ◽  
The Impact

Background. The current study evaluated the compressive, flexural and impact strengths of heat-cured acrylic resins reinforced by TiO2 nanoparticles (NPs). Methods. TiO2 NPs were provided and characterized using scanning electron microscopy (SEM) to determine their morphology and crystalline structure. For three mechanical tests, 12 acrylic resin groups (n=9), totaling 108 specimens, were prepared using a special mold for each test, with TiO2 nanoparticle contents of 0, 0.5, 1 or 2 wt% in different groups. After curing, the compressive, flexural and impact strengths of the specimens were examined according to ISO 1567. Results. In the SEM and XRD study of TiO2 NPs, anatase was identified as the major crystalline phase followed by rutile (average particle size: 20.4 nm). SEM images showed that the nanocomposite with 1 wt% NPs had a more homogenized blend. 1 wt% TiO2 nanocomposite exhibited a higher, but non-significant, impact strength compared to the controls. ANOVA showed significant differences in the impact and flexural strengths between nanocomposites with various contents of TiO2 NPs. Conclusion. The nanocomposite with 1 wt% TiO2 NPs exhibited fewer micro-pores and micro-cracks in the SEM cross-sections. A non-significant increase was also observed in the impact strength with TiO2 NPs at 1 wt%. Further increase in TiO2 NPs decreased both the impact and flexural strengths. The compressive strength of the heat-cured acrylic resin was not affected by the incorporation of NPs.

Comparison of hermetic sealing using SAC and SnPb solder for a MEMS pressure sensor

2016 ◽  
Vol 2016 (DPC) ◽  
pp. 000464-000487
Author(s):  
Maaike M. Visser Taklo ◽  
Branson Belle ◽  
Joachim Seland Graff ◽  
Astrid-Sofie Vardøy ◽  
Elisabeth Ramsdal
Keyword(s):  
Cross Sections ◽  
Pressure Sensors ◽  
Thick Layer ◽  
Long Term Effects ◽  
Soldering Process ◽  
Long Term Stability ◽  
Hermetic Seal ◽  
Reduced Rate ◽  
Mems Pressure Sensors

In order to minimize the influence of packaging stress on the signal of MEMS pressure sensors, the pressure inlet can be reduced in footprint and mechanically decoupled from the mechanically moving parts. Moreover, the formation of a hermetic seal between the sensor inlet and an external inlet becomes more challenging as the footprint is reduced. Soldering is a preferred solution as a hermetic seal is achievable despite some surface roughness at the surfaces to be joined. However, the metallization on the MEMS, the solder and the metallization on the external inlet must be carefully matched to assure long term stability; the solder will react quickly with the metal layers deposited on the surfaces during the reflow process and later at a reduced rate during storage and application. The formation of intermetallic compounds (IMC) can catastrophically degrade the integrity of a joint if large amounts of voids are formed or the mechanical compliance significantly reduces as a result of the IMC formation. The metallization alternatives for the MEMS in this case were sputtered TiW/Au and NiCr/Au. The TiW and NiCr are adhesion layers whereas the Au is applied as a wetting layer which is normally fully consumed during the soldering process. A thick layer of plated Au, or a thick layer of plated Ni with a thin surface finish layer of Au, were possible metallization alternatives for the external inlet. Dewetting of solder from TiW is frequently mentioned in literature, but less conclusive work is published about soldering to NiCr/Au [1–3]. In particular, limited work has been published on long term effects of soldering to NiCr/Au surfaces using a SAC solder. In this work TiW and NiCr were compared as adhesion layers. In addition, SAC and SnPb were compared as solder, and Au and Ni/Au were compared as metallization on the external inlet. A total of 10–20 assemblies were prepared for each of 12 tested combinations. Half of the assemblies were exposed to high temperature storage (HTS) for ~300 hours at 130–150 °C. Shear testing and inspection of fracture surfaces and cross sections using light microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were performed for samples

scholarly journals Dendritic Structure Analysis of CMSX-4 Cored Turbine Blades Roots

2016 ◽  
Vol 61 (2) ◽  
pp. 1129-1134 ◽  
Author(s):  
J. Krawczyk
Keyword(s):  
Single Crystal ◽  
Cross Sections ◽  
Induction Furnace ◽  
Turbine Blades ◽  
Dendritic Structure ◽  
Root Structure ◽  
Sem Images ◽  
X Ray ◽  
Nickel Based Superalloy

Abstract The microstructure of as-cast cored turbine blades roots, made of the single-crystal CMSX-4 nickel-based superalloy was investigated. Analysed blades were obtained by directional solidification technique in the industrial ALD Bridgman induction furnace. The investigations of the microstructure of blades roots were performed using SEM and X-ray techniques including diffraction topography with the use of Auleytner method. Characteristic shapes of dendrites with various arrangement were observed on the SEM images taken from the cross-sections, made transversely to the main blades axis. The differences in quality of the structure in particular areas of blades roots were revealed. Based on the results, the influence of cooling bores on blades root structure was analysed and the changes in the distribution and geometry of cooling bores were proposed.

Study on the Performance of Nano-CaCO3 and LLDPE Based Artificial Turf Fibers

2011 ◽  
Vol 332-334 ◽  
pp. 1077-1081
Author(s):  
Hong Ling Yi ◽  
Wei Shan Wang ◽  
Heng Lin ◽  
Wei Guang Gong ◽  
Ting Wei ◽  
...  
Keyword(s):  
Cross Sections ◽  
Tensile Force ◽  
Accelerated Aging ◽  
Artificial Turf ◽  
Sem Images ◽  
Crystallinity Degree ◽  
Elongation At Break ◽  
Caco3 Content ◽  
New Type ◽  
Strength Retention

In this paper, a new type of LLDPE/nano CaCO3 composite based artificial turf yarns with good tensile property and UV resistance is introduced. The effect of nano CaCO3content on tensile properties shows that the tensile force reached the maximum value when the CaCO3 content is about 7wt%, and the elongation at break gets to the highest point at 10wt%. After 3000h UV accelerated aging, the nano-CaCO3 and LLDPE based artificial turf fiber yarns has tensile strength retention about 87%, and the elongation at break is higher than LLDPE. DSC results shows that with the increase of nano-CaCO3 content, the crystallization temperature gradually increased, and the crystallinity degree declined. SEM images of cross sections of monofilament fibers show that nano CaCO3 had a good dispersion in monofilament fiber matrix. These reasons give rise to the improved mechanical properties of turf yarns.

Effect of Temperature on the Purity, Particle Size and Morphology of Fe2O3 Nanomaterials

2014 ◽  
Vol 895 ◽  
pp. 305-308 ◽  
Author(s):  
Abdul Rahman Noor Azreen ◽  
Norlida Kamarulzaman ◽  
Nurhanna Badar ◽  
Mustaffa Nur Amalina ◽  
Kamarudin Norashikin
Keyword(s):  
Effect Of Temperature ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Xrd Pattern ◽  
Weak Organic Acid ◽  
Irregular Shapes ◽  
Three Samples ◽  
Different Temperatures ◽  
Particle Size And Morphology ◽  
Size And Morphology

Iron Oxide, Fe2O3, has extensively been studied by many researchers because of their important uses for various applications such as magnetic storages, catalysts, anode, gas sensors and biomedical applications. In our work, Fe2O3 have been synthesized via a new self-propagating combustion (SPC) route using a weak organic acid as an oxidant. The precursor was annealed at three different temperatures. Three samples of Fe2O3 heated at 300 °C, 600 °C and 800 °C for 24 hours were characterized using X-Ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM). The XRD pattern confirms that the crystal structure for both 600 °C and 800 °C samples are rhombohedral while for the 300 °C sample, rhombohedral and cubic phases are present. The SEM images showed that the 300 °C and 600 °C materials have irregular shapes. For the 800 °C sample the materials seem to be more crystalline with individual polyhedral shapes.

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