Technical Library | 2019-07-10 23:36:14.0
Pockets of gas, or voids, trapped in the solder interface between discrete power management devices and circuit assemblies are, unfortunately, excellent insulators, or barriers to thermal conductivity. This resistance to heat flow reduces the electrical efficiency of these devices, reducing battery life and expected functional life time of electronic assemblies. There is also a corresponding increase in current density (as the area for current conduction is reduced) that generates additional heat, further leading to performance degradation.
Technical Library | 2023-09-07 14:54:10.0
A global manufacturer of a broad line of electronic interconnect solutions worked with us to dispense conductive adhesive EpoTek H20E-FC. EpoTek H20E-FC is a two-component, electrically conductive, snap curing epoxy for photovoltaic thin film module stringing, semiconductor packaging and PCB circuit assembly. The primary goal was filling a rectangular cavity on a connector. The epoxy needed to fill the connector to the top of the walls in less than three seconds.
Technical Library | 2020-10-14 14:33:36.0
Epoxy based adhesives are prevalent interface materials for all levels of electronic packaging. One reason for their widespread success is their ability to accept fillers. Fillers allow the adhesive formulator to tailor the electrical and thermal properties of a given epoxy. Silver flake allow the adhesive to be both electrically conductive and thermally conductive. For potting applications, heat sinking, and general encapsulation where high electrical isolation is required, aluminum oxide has been the filler of choice. Today, advanced Boron Nitride filled epoxies challenge alternative thermal interface materials like silicones, greases, tapes, or pads. The paper discusses key attributes for designing and formulating advanced thermally conductive epoxies. Comparisons to other common fillers used in packaging are made. The filler size, shape and distribution, as well as concentration in the resin, will determine the adhesive viscosity and rheology. Correlation's between Thermal Resistance calculations and adhesive viscosity are made. Examples are shown that determination of thermal conductivity values in "bulk" form, do not translate into actual package thermal resistance. Four commercially available thermally conductive adhesives were obtained for the study. Adhesives were screened by shear strength measurements, Thermal Cycling ( -55 °C to 125 °C ) Resistance, and damp heat ( 85 °C / 85 %RH ) resistance. The results indicate that low modulus Boron Nitride filled epoxies are superior in formulation and design. Careful selection of stress relief agents, filler morphology, and concentration levels are critical choices the skilled formulator must make. The advantages and limitations of each are discussed and demonstrated.
Technical Library | 2010-11-04 19:56:25.0
Conductive Adhesives represent an intrinsically clean, simple and logical solution for a myriad of electrical interconnect challenges. Adhesives not only provide a "lead-free", "no clean" alternative to solder, these highly compatible materials offer viab
Technical Library | 2010-08-19 18:33:17.0
The silver end termination plays an important role for multilayer chip inductors. A basic requirement is to achieve excellent electrical properties with superior adhesion to the chip. Driven by the increasing price of silver, interest has been shown to
Technical Library | 2013-01-18 02:42:14.0
ENIG (Electroless Nickel/Immersion Gold) is to deposit nickel gold plating which has good solderability, wear resistance , leveling appearance and small electric resistance. It included 4 steps that are pretreatment, immersion nickel, immersion gold and Post treatment...
Technical Library | 2016-01-07 19:13:23.0
The purpose of this study is to investigate the effect of plasma surface modification to improve adhesion strength between polytetrafluoroethylene (PTFE) and electroless copper plating. PTFE is widely used in many industries because of its unique electrical, thermal, and mechanical characteristics. However, because of its low surface energy, it is difficult to acquire enough adhesion strength between PTFE and other substances without surface modification. Plasma is well known as one of the surface modification techniques that improve adhesion strength.
Technical Library | 2021-08-11 00:55:44.0
In this article, the influence of shrinkage tensile stress in potting materials on the anti-overload performance of a circuit board was studied. Firstly, the phenomenon of shrinkage tensile stress in common potting materials was analyzed, and it was found that the commonly used potting adhesives displayed large shrinkage characteristics. Secondly, a small experiment was set up to verify that the shrinkage tensile stress of potting adhesives would lead to printed circuit board (PCB) deformation, and the shrinkage stress was contrary to the acceleration direction of overload. Thirdly, the influence of potting adhesives on the overload resistance of the PCB was analyzed.
Technical Library | 2007-11-01 17:16:07.0
This paper discusses micro-filled epoxy-based conducting adhesives modified with nanoparticles, conducting polymers, and low melting point (LMP) fillers for z-axis interconnections, especially as they relate to package level fabrication, integration,
Technical Library | 2013-03-28 16:18:22.0
For the last couple of years, the main concerns regarding the electrical performance of blank PCB boards were impedance and ohmic resistance. Just recently, the need to reduce insertion loss came up in discussions with blank board customers (...) The paper describes the test vehicle and the testing methodology and discusses in detail the electrical performance characteristics. The influence of the independent variables on the performance characteristics is presented. Finally the thermal reliability of the boards built applying different copper foils and oxide replacements was investigated.
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