Technical Library | 2017-06-29 16:39:30.0
Currently there is no industry standard test method for measuring dielectric properties of circuit board materials at frequencies greater than about 10 GHz. Various materials vendors and test labs take different approaches to determine these properties. It is common for these different approaches to yield varying values of key properties like permittivity and loss tangent. The D-24C Task Group of IPC has developed this round robin program to assess these various methods from the "bottom up" to determine if standardized methods can be agreed upon to provide the industry with more accurate and valid characteristics of dielectrics used in high-frequency and high-speed applications.
Technical Library | 2017-10-12 15:45:25.0
The risk associated with whisker growth from pure tin solderable terminations is fully mitigated when all of the pure tin is dissolved into tin-lead solder during SMT reflow. In order to take full advantage of this phenomenon, it is necessary to understand the conditions under which such coverage can be assured. A round robin study has been performed by IPC Task group 8-81f, during which identical sets of test vehicles were assembled at multiple locations, in accordance with IPC J-STD-001, Class 3. All of the test vehicles were analyzed to determine the extent of complete tin dissolution on a variety of component types. Results of this study are presented together with relevant conclusions and recommendations to guide high reliability end-users on the applicability and limitations of this mitigation strategy.
Technical Library | 2017-04-20 13:51:14.0
The one constant in electronics manufacturing is change. Moore's Law, which successfully predicted a rate of change at which transistor counts doubled on Integrated Circuits (ICs) at lower cost for decades, is ceding to be an appropriate prediction tool. Increasing technical and economic requirements, deriving from the semiconductor environment, are cascaded down to the printed circuit and in particular to the IC substrate manufacturers. This is both a challenge and an opportunity for IC Substrate manufacturers, when dealing with the demands of the packaging market. (...)This paper introduces two new electroless copper baths developed for IC substrates manufacturing based on Semi Additive Process (SAP) technology (hereafter referred to as E'less Copper IC) and HDI production (hereafter referred to as E'less Copper HDI) and optimized for high throw into BMVs. An introduction to reliable throwing power measurement methods based on scanning electron microscope (SEM) is given, followed by a compilation and discussion of key performance criteria for each application, namely throwing power, copper adhesion on the substrate, dry film adhesion and reliability.
Technical Library | 2021-11-03 17:05:39.0
Additively printed circuits provide advantages in reduced waste, rapid prototyping, and versatile flexible substrate choices relative to conventional circuit printing. Copper (Cu) based inks along with intense pulsed light (IPL) sintering can be used in additive circuit printing. However, IPL sintered Cu typically suffer from poor solderability due to high roughness and porosity. To address this, hybrid Cu ink which consists of Cu precursor/nanoparticle was formulated to seed Cu species and fill voids in the sintered structure. Nickel (Ni) electroplating was utilized to further improve surface solderability. Simulations were performed at various electroplating conditions and Cu cathode surface roughness using the multi-physics finite element method. By utilizing a mask during IPL sintering, conductivity was induced in exposed regions; this was utilized to achieve selective Ni-electroplating. Surface morphology and cross section analysis of the electrodes were observed through scanning electron microscopy and a 3D optical profilometer. Energy dispersive X-ray spectroscopy analysis was conducted to investigate changes in surface compositions. ASTM D3359 adhesion testing was performed to examine the adhesion between the electrode and substrate. Solder-electrode shear tests were investigated with a tensile tester to observe the shear strength between solder and electrodes. By utilizing Cu precursors and novel multifaceted approach of IPL sintering, a robust and solderable Ni electroplated conductive Cu printed electrode was achieved.
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