Time-Dependent Ductility of Electro-Deposited Copper

Mechanical ductility property of copper deposits is one of the most important factors necessary to provide a reliable component for the flexible printed circuit boards. Copper deposits are usually fabricated by either an electroless technique or an electrode position process. Among many parameters controlling the deposits quality, it is believed that the current density, bath temperature, the film thickness, annealing temperature and time, and the presence of impurities exhibit particularly strong influences on the mechanical ductility property. In our preliminary studies, it was found that the ductility obtained by the mechanical bulge testing showed a three-stage characteristics in terms of a room temperature annealing; namely (i) initial low ductility regime (from the right-after-copper-deposition until 12 hours aged at room temperature), (ii) transitional rapid increasing ductility regime (from 12 hours to 24 hours), and (iii) the high ductility regime (after 24 hours). In this study, X-ray diffraction analyses of the diffracted line width, the microstrain from which the dislocation density was estimated, residual macrostress, and the scanning electron microscopic observations were conducted and results were correlated with the characteristic three-stage ductility change behavior described above. Results of this study indicate that grain size and residual stress changes are strongly associated with improvement in copper ductility during the room temperature annealing.

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Plastic deformation of θ ' in Al-4%Cu alloy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100110027 ◽

1978 ◽

Vol 36 (1) ◽

pp. 576-577

Author(s):

Shrikant P. Bhat

Keyword(s):

Deformation Behavior ◽

Room Temperature ◽

Electron Microscopic Observation ◽

Bulk Alloy ◽

Electron Microscopic ◽

Cu Alloy ◽

Cu Alloys ◽

Orowan Mechanism ◽

The Subject ◽

Cyclic Straining

deformation behavior of Al-Cu alloys aged to contain θ ' has been the subject of many investigations (e.g., Ref. 1-5). Since θ ' is strong and hard, dislocations bypass θ ' plates (Orowan mechanism) at low strains. However, at high strains the partially coherent θ ' plates are probably sheared, although the mechanism is complex, depending on the form of deformation. Particularly, the cyclic straining of the bulk alloy is known to produce gross bends and twists of θ '. However, no detailed investigation of the deformation of θ ' has yet been reported; moreover, Calabrese and Laird interpreted the deformation of θ ' as largely being elastic.During an investigation of high temperature cyclic deformation, the detailed electron-microscopic observation revealed that, under reversed straining conditions, θ ' particles are severely distorted--bent and twisted depending on the local matrix constraint. A typical electronmicrograph, showing the twist is shown in Fig. 1. In order to establish whether the deformation is elastic or plastic, a sample from a specimen cycled at room temperature was heated inside the microscope and the results are presented in a series of micrographs (Fig. 2a-e).

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Effects of Mg2+ on Chromatic Structure in Isolated Chicken Liver Nuclei

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100158194 ◽

1990 ◽

Vol 48 (3) ◽

pp. 130-131

Author(s):

Soichiro Arai ◽

Yuh H. Nakanishi

Keyword(s):

Chromatin Structure ◽

Room Temperature ◽

Osmium Tetroxide ◽

Divalent Cations ◽

Chromatin Condensation ◽

Chicken Liver ◽

Electron Microscopic ◽

Razor Blade ◽

Microscopic Studies ◽

Liver Nuclei

Although many electron microscopic studies on extracted chromatin have provided considerable information on chromatin condensation induced by divalent cations, there is only a little literature available on the effects of divalent cations on chromatin structure in intact nuclei. In the present study, the effects of Mg2+ on chromatin structure in isolated chicken liver nuclei were examined over a wide concentration range of Mg2+ by scanning electron microscopy.Nuclei were prepared from chicken liver by the method of Chauveau et al. with some modifications. The nuclei were suspended in 25 mM triethanolamine chloride buffer (pH7.4) with 1 mM EDTA or in the buffer with concentrations of MgCl2 varying from 1 to 50 mM. After incubation for 1 min at 0°C, glutaraldehyde was added to 1.8% and the nuclei were fixed for 1 h at 4°C. The fixed nuclei were mixed with 15% gelatin solution warmed at about 40°C, and kept at room temperature until the mixture set. The gelatin containing the nuclei was fixed with 2% glutaraldehyde for 2-4 h, and cut into small blocks. The gelatin blocks were conductive-stained with 2% tannic acid and 2% osmium tetroxide, dehydrated in a graded series of ethanol, and freeze-cracked with a razor blade in liquid nitrogen.

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Formation of a unique glass by spark plasma sintering of a zeolite

Journal of Materials Research ◽

10.1557/jmr.2009.0385 ◽

2009 ◽

Vol 24 (10) ◽

pp. 3241-3245 ◽

Cited By ~ 17

Author(s):

Lianjun Wang ◽

Wan Jiang ◽

Lidong Chen ◽

Zhijian Shen

Keyword(s):

Spark Plasma Sintering ◽

Glass Sample ◽

Room Temperature ◽

Vickers Microhardness ◽

Simple Approach ◽

Electron Microscopic ◽

Plasma Sintering ◽

Transmission Electron ◽

Transmission Electron Microscopic ◽

Spark Plasma

A simple approach, order–disorder transition (ODT), has been developed to synthesize a novel glass using ZSM-5 as starting materials. In this process, the ZSM-5 powders were pressed uniaxially in a graphite die and rapidly sintered using spark plasma sintering (SPS). High-resolution transmission electron microscopic images revealed that a few crystalline zeolite fragments were still preserved locally inside the SPS consolidated sample. Vickers microhardness and fracture toughness of this as-prepared transparent glass sample at room temperature reaches 7.3 ± 0.2 GPa and 2.0 ± 0.3MPa·m1/2, respectively. It is very interesting that these novel bulk transparent glasses exhibit ultraviolet photoluminescence (PL) properties at about ∼360 nm.

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Ultrasonic Bonding of Electrodes of Rigid and Flexible Printed Circuit Boards with Non-Conductive Film (NCF)

The Journal of Adhesion ◽

10.1080/00218460902880198 ◽

2009 ◽

Vol 85 (6) ◽

pp. 341-350 ◽

Cited By ~ 1

Author(s):

Jong-Bum Lee ◽

Ja-Myeong Koo ◽

Jong-Woong Kim ◽

Bo-In Noh ◽

Jong-Gun Lee ◽

...

Keyword(s):

Printed Circuit Boards ◽

Circuit Boards ◽

Printed Circuit ◽

Ultrasonic Bonding ◽

Conductive Film ◽

Flexible Printed Circuit

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HCl Gas Sensor Coating Based on Poly(N-isopropylacrylamide) Nanoparticles Prepared from Water-Methanol Binary Solvent

Sensors ◽

10.3390/s18103283 ◽

2018 ◽

Vol 18 (10) ◽

pp. 3283 ◽

Cited By ~ 3

Author(s):

Masanobu Matsuguchi ◽

Shinnosuke Fujii

Keyword(s):

Room Temperature ◽

Pure Water ◽

Electron Microscopic Observation ◽

Spherical Particles ◽

Binary Solvent ◽

Electron Microscopic ◽

Coated Nanoparticles ◽

Water Solvent ◽

Scanning Electron Microscopic ◽

Hcl Gas

Poly(N-isopropylacrylamide) (PNIPAM) nanoparticles formed in water-methanol binary solvent were successfully deposited on a resonator surface at room temperature by exploiting the cononsolvency effect on the phase transition of PNIPAM aqueous solutions. Scanning electron microscopic observation revealed that the nanoparticles were secondary and made up of agglomerated primary spherical particles of about 10-nm diameter, buried in the film. The magnitude of the sensor response toward HCl gas was larger than that of the nanoparticle sensor prepared from pure water solvent, and the sensitivity to 1 ppm of HCl of sensor-coated nanoparticles based on the present method was 3.3 Hz/ppm. The recovery of the sensors was less than 90% at first cycle measurement, but had improved to almost 100% at the third cycle.

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FAILURE ANALYSIS OF DISCOLORED ENIG PADS IN THE MANUFACTURING ENVIRONMENT

International Symposium on Microelectronics ◽

10.4071/isom-wp24 ◽

2014 ◽

Vol 2014 (1) ◽

pp. 000653-000661

Author(s):

Monika Marciniak ◽

Michael Meagher ◽

Jon Davis ◽

Jack Josefowicz

Keyword(s):

Failure Analysis ◽

Printed Circuit Boards ◽

Electroless Nickel ◽

Manufacturing Environment ◽

Electron Microscopic ◽

Verification Method ◽

Surface Finishes ◽

Line Process ◽

Cleaning Methods ◽

Surface Examination

Manufacturing of electronic assemblies using printed circuit boards (PCBs) with electroless nickel/immersion gold (ENIG) surface finishes requires front-end PCB evaluation that will guarantee that good quality product enters the assembly line. The most common is an IPC-4552 mandated plating thicknesses verification of 3-6μm and a minimum of 0.05μm for nickel and gold, respectively. Coupled with visual examination, this verification method suffices for general PCB acceptance but may not be robust enough in cases where ENIG plating in PCBs is compromised. That poses challenges in the manufacturing environment, where resulting latent defects are detected in downstream processes but not at upfront incoming inspection. Manifestation of such latent anomaly was observed in the form of ENIG pad discoloration with variations from yellow, red or grey discolored surfaces to a more pronounced plating degradation, such as corrosive pitting. The launched failure analysis involved evaluation of manufacturing processes suspected to contribute to the cause of the condition. Effects of thermal processes, cleaning methods, soldering, parylene deposition and factory cleanliness were examined thoroughly. Concurrently, metallurgical analysis of ENIG pads was performed, where samples were subjected to scanning electron microscopic/energy dispersive x-ray spectroscopic (SEM/EDX) cross section analysis, Auger electron spectroscopy (AES) and gold (Au) and electroless nickel (Ni) surface examination. The resulting analysis revealed a highly porous electroless nickel coating with deep crevasses and fissures penetrating down to the base copper (Cu) layer. These open nickel boundaries were attributed to the corrosive environment within ENIG plating, which resulted in the pad surface discoloration. The root cause of ENIG pad discoloration and pitting was traced back to poor ENIG line process controls. Subsequent introduction of a nickel controller into the ENIG line were the implemented countermeasures. To mitigate the effects of discoloration at the electronic assembly level, a tinning process was implemented to prevent nickel plating oxidation and to ensure that good wettability for reliable solder joints was maintained.

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Mechanical Test of FPCB and Failure Analysis by Simulation

Volume 3: ASME/IEEE 2009 International Conference on Mechatronic and Embedded Systems and Applications; 20th Reliability, Stress Analysis, and Failure Prevention Conference ◽

10.1115/detc2009-87200 ◽

2009 ◽

Author(s):

Jian Zhong ◽

Ping Yang ◽

Jian-ping Li ◽

Hai-bo Sun ◽

Quayle Chen ◽

...

Keyword(s):

Failure Analysis ◽

Printed Circuit Boards ◽

Simulation Analysis ◽

Mechanical Test ◽

Mechanical Tests ◽

Stress Distributions ◽

Circuit Boards ◽

Printed Circuit ◽

Depth Analysis ◽

Flexible Printed Circuit

The paper mainly presented mechanical test and failure analysis methods to reliability study of a new FPCB (Flexible Printed Circuit Boards). Mechanical tests include flexural test, tensile test and flexural fatigue and ductility test. As to simulation analysis, the stress distributions of FPCB under bending and tensile conditions were gained by simulations. Through in-depth analysis of the testing results, the mechanical reliability of FPCB was known detailed. The research provides an approach to improve FPCB performance.

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