Customized Circuit Interconnect and Repair by Laser Seeding and Constriction-Induced Plating.

1990 ◽  
Vol 203 ◽  
Author(s):  
Julian P. Partridge ◽  
C. Julian Chen
Keyword(s):  
Equilibrium Potential ◽  
Palladium Acetate ◽  
Process Window ◽  
Acetate Solution ◽  
Cross Sectional ◽  
Mechanical And Electrical Properties ◽  
Copper Electrolyte ◽  
Ion Laser ◽  
Novel Method ◽  
Current Densities

ABSTRACTA novel method has been developed for producing customized copper interconnections on thermally-sensitive substrates by laser seeding followed by constrictioninduced electroplating. A polyimide, polytetrafluoroethylene, or glass-epoxy substrate is first sprayed with palladium acetate solution. 500 nm thick palladium interconnects are then formed using a 514 nm argon ion laser (10 mW - 50 mW) to selectively pyrolyze the acetate film. After cleaning, the part is immersed in an acid copper electrolyte and an alternating current (0.1 Amp - 2.0 Amp) passed through the palladium seed. Joule heating produces a cathodic shift in the equilibrium potential (dε0/dT = 0.63 mV/degree) which causes electrodeposition of copper along the seeded connection.Cross-sectional microscopy and electrochemical polarization studies show that local plating current densities of 10 mA/cm2 produce 1000 εm × 25 εm × 10 εm line geometries exhibiting excellent mechanical and electrical properties. The large process window suggests that customization and repair on lincwidths below 1 mil (25 εm) should be achievable routinely.

Diagnostics of metal samples using the results of experimental and theoretical study of positively charged microparticles formed upon sample destruction

2018 ◽  
Vol 84 (10) ◽  
pp. 23-28
Author(s):  
D. A. Golentsov ◽  
A. G. Gulin ◽  
Vladimir A. Likhter ◽  
K. E. Ulybyshev
Keyword(s):  
Experimental Data ◽  
Early Stage ◽  
Experimental Studies ◽  
Material Model ◽  
Total Charge ◽  
Cross Sectional ◽  
Practical Applications ◽  
Mechanical And Electrical Properties ◽  
Order Of Magnitude ◽  
Using Data

Destruction of bodies is accompanied by formation of both large and microscopic fragments. Numerous experiments on the rupture of different samples show that those fragments carry a positive electric charge. his phenomenon is of interest from the viewpoint of its potential application to contactless diagnostics of the early stage of destruction of the elements in various technical devices. However, the lack of understanding the nature of this phenomenon restricts the possibility of its practical applications. Experimental studies were carried out using an apparatus that allowed direct measurements of the total charge of the microparticles formed upon sample rupture and determination of their size and quantity. The results of rupture tests of duralumin and electrical steel showed that the size of microparticles is several tens of microns, the particle charge per particle is on the order of 10–14 C, and their amount can be estimated as the ratio of the cross-sectional area of the sample at the point of discontinuity to the square of the microparticle size. A model of charge formation on the microparticles is developed proceeding from the experimental data and current concept of the electron gas in metals. The model makes it possible to determine the charge of the microparticle using data on the particle size and mechanical and electrical properties of the material. Model estimates of the total charge of particles show order-of-magnitude agreement with the experimental data.

Electromigration in Solder Joints for High Temperature Flip-Chip Application

2011 ◽  
Vol 2011 (DPC) ◽  
pp. 002481-002506
Author(s):  
Mathias Nowottnick ◽  
Andreas Fix
Keyword(s):  
High Temperature ◽  
Current Density ◽  
Flip Chip ◽  
Solder Joints ◽  
Metallographic Analysis ◽  
Solder Alloys ◽  
Directed Movement ◽  
Cross Sectional ◽  
Current Densities ◽  
And Migration

The electromigration effects in chip metallization and wire bonds are well known and detailed investigated. Current density could be extremely high because of the small size of the cross sectional area of conductors. This can cause a migration of metal atoms toward the electrical field, so current densities up to 106 A/cm2 are possible. In comparison with chip structures are the usual solder joints of flip chips relatively thick. But the homologue temperature of solder alloys, typically based on tin, is also much higher than for gold or aluminum wires. For instance a SAC solder alloy is naturally preheated up to 0.6 homologue temperature, for high temperature application with 125 °C operating temperature even more than 0.8. This means, that atoms are very agile and a directed movement needs only lower field strength. Additionally is the specific resistance of solder alloys tenfold higher than for aluminum, copper or silver. So is the self-heating of solder joints not negligible. This contribution shows the test results of flip-chip assemblies, loaded with different current densities and stored at 125 °C ambient temperature. At the end of life of a significant number of test chips, a metallographic analysis shows the causing failure effects and weak spots of assemblies. Accompanying simulations help to explain the interaction between current density and migration effects.

scholarly journals Study on Electromigration Effects and IMC Formation on Cu–Sn Films Due to Current Stress and Temperature

2020 ◽  
Vol 10 (24) ◽  
pp. 8893
Author(s):  
Zhao-Ying Wang ◽  
Nhat Minh Dang ◽  
Po-Hsun Wang ◽  
Terry Yuan-Fang Chen ◽  
Ming-Tzer Lin
Keyword(s):  
Intermetallic Compound ◽  
Growth Mechanism ◽  
Current Density ◽  
Structural Changes ◽  
Defect Formation ◽  
Copper Substrate ◽  
Signal Delay ◽  
Cross Sectional ◽  
Current Densities

In this study, the effects of electromigration on a solder/copper substrate due to temperature and current density stress were investigated. The copper–tin (Cu–Sn) film samples were subjected under a fixed current and various heating conditions (130 °C and 180 °C) and current densities (different cross-sectional areas). The micro-structural changes and intermetallic compound (IMC) formation were observed, and failure phenomena (brittle cracks, voids, bumps, etc.) on the structures of samples were discussed. The results showed that the IMC thickness increased as the temperature and current density increased. Moreover, it was found that the higher the temperature and current density was, the greater the defects that were observed. By adjusting the designs of sample structures, the stress from the current density can be decreased, resulting in reduced failure phenomena, such as signal delay, distortion, and short circuiting after long-term use of the material components. A detailed IMC growth mechanism and defect formation were also closely studied and discussed.

Characterization of pulsed laser deposited MoS2 by transmission electron microscopy

1993 ◽  
Vol 8 (11) ◽  
pp. 2933-2941 ◽  
Author(s):  
S.D. Walek ◽  
M.S. Donley ◽  
J.S. Zabinski ◽  
V.J. Dyhouse
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Solid Phase ◽  
Analytical Electron Microscopy ◽  
Pulsed Laser ◽  
Cross Sectional ◽  
Aerospace Applications ◽  
Transmission Electron ◽  
Novel Method

Molybdenum disulfide is a technologically important solid phase lubricant for vacuum and aerospace applications. Pulsed laser deposition of MoS2 is a novel method for producing fully dense, stoichiometric thin films and is a promising technique for controlling the crystallographic orientation of the films. Transmission electron microscopy (TEM) of self-supporting thin films and cross-sectional TEM samples was used to study the crystallography and microstructure of pulsed laser deposited films of MoS2. Films deposited at room temperature were found to be amorphous. Films deposited at 300 °C were nanocrystalline and had the basal planes oriented predominately parallel to the substrate within the first 12–15 nm of the substrate with an abrupt upturn into a perpendicular (edge) orientation farther from the substrate. Spherically shaped particles incorporated in the films from the PLD process were found to be single crystalline, randomly oriented, and less than about 0.1 μm in diameter. A few of these particles, observed in cross section, had flattened bottoms, indicating that they were molten when they arrived at the surface of the growing film. Analytical electron microscopy (AEM) was used to study the chemistry of the films. The x-ray microanalysis results showed that the films have the stoichiometry of cleaved single crystal MoS2 standards.

Novel method for selecting slices of the same cross-sectional view from digital tomosynthesis for monitoring posterior spinal instrumentation

2021 ◽  
Vol 92 ◽  
pp. 183-188
Author(s):  
Eriko Okano ◽  
Yuki Hara ◽  
Atsuo Ito ◽  
Kentaro Mataki ◽  
Yasukazu Totoki ◽  
...  
Keyword(s):  
Spinal Instrumentation ◽  
Digital Tomosynthesis ◽  
Cross Sectional ◽  
Novel Method

A Novel Method for the Measurement of Slight Wear

2013 ◽  
Vol 750-752 ◽  
pp. 1987-1991
Author(s):  
Jian Hua Yang ◽  
Xing Jian Ma ◽  
Lu Fei Rong ◽  
Bo Liu ◽  
Jia Yan Yu ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Measurement Accuracy ◽  
Processing Technology ◽  
Wear Testing ◽  
Cross Sectional ◽  
Speed Up ◽  
Novel Method ◽  
Pretreatment Conditions ◽  
Weighing Method

The characterization of surface wear resistance of materials usually relies on the measurement of slight wear. There are two obvious shortcomings for weighing method. In order to improve the measurement accuracy, a more intuitive and reliable method for quantitative measurement of slight wear, interference microscope method, has be given. Higher accuracy (the order of micrometer) can be achieved using the interferometry for the measurement of slight wear. The results show that the masking processing technology can ensure that all samples for wear testing and other analysis are obtained under the same pretreatment conditions and vacuum processing conditions, speed up the commercialization of processing technology, and comparing the cross-sectional areas of wear scars is a correct way to characterize the wear resistance of different zones.

scholarly journals Novel case-control observational method for assessing effectiveness of red-light cameras

2017 ◽  
Vol 44 (6) ◽  
pp. 407-416 ◽  
Author(s):  
Amal Jasem Abdulsalam ◽  
Dane Rowlands ◽  
Said M. Easa ◽  
Abd El Halim O. Abd El Halim
Keyword(s):  
Empirical Bayes ◽  
Red Light ◽  
Control Group ◽  
Cross Sectional ◽  
Specific Criterion ◽  
Red Light Cameras ◽  
Empirical Bayes Methods ◽  
Novel Method ◽  
Conventional Methods ◽  
Different Characteristics

Conventional methods for estimating the effect of an intervention suffer from selection bias, where the units that receive the treatment have different characteristics from those in the control group. This paper proposes a novel method that provides a specific criterion for selecting the control group. The method, called propensity score matching (PSM), was applied to the evaluation of red-light cameras (RLC) and its performance was compared with conventional cross-sectional and empirical Bayes methods. The application was performed using field data from the City of Ottawa involving 30 RLC intersections and 89 non-camera intersections observed for a period of 15 years. All three methods yielded fairly consistent results, indicating an increase in property damage collisions and a decrease in injury and fatal collisions. Given the strong theoretical basis of the PSM method and its ability to produce a more stable and reliable estimator, the method is recommended as a viable alternative to the conventional methods.

scholarly journals Influence of Ring-Shaped Beam Profiles on Process Stability and Productivity in Laser-Based Powder Bed Fusion of AISI 316L

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1989
Author(s):  
Jonas Grünewald ◽  
Florian Gehringer ◽  
Maximilian Schmöller ◽  
Katrin Wudy
Keyword(s):  
Laser Power ◽  
Scanning Speed ◽  
Process Window ◽  
Powder Bed Fusion ◽  
Aisi 316L ◽  
Process Stability ◽  
Cross Sectional ◽  
Powder Bed ◽  
Shaped Beam ◽  
Process Robustness

A major factor slowing down the establishment of additive manufacturing processes as production processes is insufficient reproducibility and productivity. Therefore, this work investigates the influence of ring-shaped beam profiles on process stability and productivity in laser-based powder bed fusion of AISI 316L. For this purpose, the weld track geometries of single tracks and multi-track segments with varying laser power, scan speed, hatch distance, and beam profile (Gaussian profile and three different ring-shaped profiles) are analyzed. To evaluate the process robustness, process windows are identified by classifying the generated single tracks into different process categories. The influence of the beam profiles on productivity is studied by analyzing the molten cross-sectional areas and volumes per time. When using ring-shaped beam profiles, the process windows are significantly larger (up to a laser power of 1050 W and a scanning speed of 1700 mm/s) than those of Gaussian beams (laser power up to 450 W and scanning speed up to 1100 mm/s), which suggests a higher process robustness and stability. With ring-shaped beam profiles, larger volumes can be stably melted per track and time. The weld tracks created with ring-shaped profiles are significantly wider than those generated with Gaussian profiles (up to factor 2 within the process window), allowing enlargement of the hatch distances. Due to the higher scanning speeds and the enlarged hatch distances for ring-shaped beam profiles, the process can be accelerated by a factor of approximately 2 in the parameter range investigated.

scholarly journals Water Activity Regulates CO2 Reduction in Gas-Diffusion Electrodes

2021 ◽  
Author(s):  
Nathan Nesbitt ◽  
Wilson Smith
Keyword(s):  
Gas Phase ◽  
Paradigm Shift ◽  
Reaction Rate ◽  
Co2 Reduction ◽  
Gas Diffusion ◽  
Equilibrium Potential ◽  
Gas Diffusion Electrodes ◽  
Reaction Thermodynamics ◽  
Current Densities ◽  
Reaction Equilibrium

<p>Electrochemical CO<sub>2</sub> reduction has recently reached current densities as high as 1 A cm<sup>-2</sup>, enabled by improving diffusion of CO<sub>2</sub> from the gas phase to the electrocatalyst by use of gas-diffusion electrodes (GDEs) and by improving electrolyte ionic conductivity with concentrated hydroxide electrolytes (7 M KOH). Despite such high solute concentrations, the dilute electrolyte assumption is commonly used to evaluate the thermodynamics of the system, specifically reaction equilibrium potential and reaction rate expression. Here we establish a paradigm shift by demonstrating how to properly include the activity of water and solutes and highlighting corrections to associated reaction thermodynamics.</p>

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