Technical Library | 2013-04-25 11:42:01.0
Specification and control of surface roughness of copper conductors within printed circuit boards (PCBs) are increasingly desirable in multi-GHz designs as a part of signal-integrity failure analysis on high-speed PCBs. The development of a quality-assurance method to verify the use of foils with specified roughness grade during the PCB manufacturing process is also important... First published in the 2012 IPC APEX EXPO technical conference proceedings.
Technical Library | 2007-10-10 23:23:40.0
Process engineers, who are seeking to achieve the most effective and reproducible thermal transfer process, look to today's forced convection ovens for applications such as flipchip, BGA, and lead-free soldering. A forced convection process to maximize thermal uniformity can be best accomplished by employing static pressure generation in what's known as "closed loop convection".
Technical Library | 2019-06-26 23:21:49.0
Copper-filled micro-vias are a key technology in high density interconnect (HDI) designs that have enabled increasing miniaturization and densification of printed circuit boards for the next generation of electronic products. Compared with standard plated through holes (PTHs) copper filled vias provide greater design flexibility, improved signal performance, and can potentially help reduce layer count, thus reducing cost. Considering these advantages, there are strong incentives to optimize the via filling process. This paper presents an innovative DC acid copper via fill formulation, for VCP (Vertical Continues Plating) applications which rapidly fills vias while minimizing surface plating.
Technical Library | 2017-09-28 16:36:33.0
These nano-coatings also refine the solder paste brick shape giving improved print definition. These two benefits combine to help the solder paste printing process produce an adequate amount of solder paste in the correct position on the circuit board pads. Today, stencil aperture area ratios from 0.66 down to 0.40 are commonly used and make paste printing a challenge. This paper presents data on small area ratio printing for component designs including 01005 Imperial (0402 metric) and smaller 03015 metric and 0201 metric chip components and 0.3 mm and 0.4 mm pitch micro BGAs.
Technical Library | 2022-09-25 20:18:33.0
Printed circuit board (PCB) bending and/or flexing is an unavoidable phenomenon that is known to exist and is easily encountered during electronic board assembly processes. PCB bending and/or flexing is the fundamental source of tensile stress induced on the electronic components on the board assembly. For more brittle components, like ceramic-based electronic components, micro-cracks can be induced, which can eventually lead to a fatal failure of the components. For this reason, many standards organizations throughout the world specify the methods under which electronic board assemblies must be tested to ensure their robustness, sometimes as a pre-condition to more rigorous environmental tests such as thermal cycling or thermal shock.
Technical Library | 2014-12-18 17:22:34.0
Manufacturing technology faces challenges with new packages/process when confronting the need for high yields. Identifying product defects associated with the manufacturing process is a critical part of electronics manufacturing. In this project, we focus on how to use AXI to identify BGA Head-in-Pillow (HIP), which is challenging for AXI testing. Our goal is to help us understand the capabilities of current AXI machines.
Technical Library | 2013-03-14 17:19:28.0
Commercial-off-the-shelf ball/column grid array packaging (COTS BGA/CGA) technologies in high reliability versions are now being considered for use in a number of National Aeronautics and Space Administration (NASA) electronic systems. Understanding the process and quality assurance (QA) indicators for reliability are important for low-risk insertion of these advanced electronic packages. This talk briefly discusses an overview of packaging trends for area array packages from wire bond to flip-chip ball grid array (FCBGA) as well as column grid array (CGA). It then presents test data including manufacturing and assembly board-level reliability for FCBGA packages with 1704 I/Os and 1-mm pitch, fine pitch BGA (FPBGA) with 432 I/Os and 0.4-mm pitch, and PBGA with 676 I/Os and 1.0-mm pitch packages. First published in the 2012 IPC APEX EXPO technical conference proceedings.
Technical Library | 2021-01-03 19:24:52.0
Reflow soldering is the primary method for interconnecting surface mount technology (SMT) applications. Successful implementation of this process depends on whether a low defect rate can be achieved. In general, defects often can be attributed to causes rooted in all three aspects, including materials, processes, and designs. Troubleshooting of reflow soldering requires identification and elimination of root causes. Where correcting these causes may be beyond the reach of manufacturers, further optimizing the other relevant factors becomes the next best option in order to minimize the defect rate.
Technical Library | 2018-02-28 22:28:30.0
Circuit functional density requirements continue to drive innovative approaches to high performance packaging. Some new approaches include; aggressive space reduction, embedded solutions, and those that offer some form of risk reduction and rework potential are now options that are being explored by customers. Requirements for assembly of these types of packages necessitate the deposition of solder paste and assembly of components into cavities of the substrates to gain z-axis density as well as area functional density. Advances in the fabrication of PWB’s with cavities using newly developed laser micro-fabrication processes along with increased circuit pitch density of 50 micron lines and spaces permit new applications for high performance electronic substrates. First published at SMTA Pan Pacific Symposium
Technical Library | 2015-08-20 15:18:38.0
Increasing system integration and component densities continue to significantly reduce the opportunity to access nets using standard test points. Over time the size of test points has been drastically reduced (as small as 0.5 mm in diameter) but current product design parameters have created space and access limitations that remove even the option for these test points. Many high speed signal lines have now been restricted to inner layers only. Where surface traces are still available for access, bead probe technology is an option that reduces test point space requirements as well as their effects on high speed nets and distributes mechanical loading away from BGA footprints enabling test access and reducing the risk of mechanical defects associated with the concentration of ICT spring forces under BGA devices. Building on Celestica's previous work characterizing contact resistance associated with Pr-free compatible surface finishes and process chemistry; this paper will describe experimentation to define a robust process window for the implementation of bead probe and similar bump technology that is compatible with standard Pb-free assembly processes. Test Vehicle assembly process, test methods and "Design of Experiments" will be described. Bead Probe formation and deformation under use will also be presented along with selected results.
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