Oct 29, 2015 | Chen Xu, Yunhu Lin; Alcatel-Lucent, Yuan Zeng, Pericles A. Kondos; Unovis-Solutions.
With the electronic industry moving towards lead-free assembly, traditional SnPb-compatible laminates need to be replaced with lead-free compatible laminates that can withstand the higher reflow temperature required by lead-free solders. Lead-free compatible laminates with improved heat resistance have been developed to meet this challenge but they are typically more brittle than SnPb laminates causing some to be more susceptible to pad cratering. In this paper, two novel approaches for minimizing pad cratering will be discussed. Preliminary results which validate the two approaches will also be presented....
Oct 22, 2015 | Linda Woody, William Fox; Lockheed Martin Missiles and Fire Control
The objective of this study is to evaluate conformal coatings for mitigation of tin whisker growth. The conformal coatings chosen for the experiment are acrylic, polyurethane and parylene. Also included in this paper are tin whisker inspection results of tin-plated braiding and wire that was exposed to an environment of 50°C with 50% relative humidity for over five years....
Publisher: Lockheed Martin Corporation
Oct 15, 2015 | Dave Sommervold, Chris Parker, Steve Taylor, Garry Wexler
The ever expanding growth in the use of insulated metal substrates (IMS) in power electronics requires a focus on material and mechanical configuration for each application. By optimizing the material makeup and printed board format, performance and reliability expectations can be further achieved. The thermal performance and electrical isolation needs are driven by the power requirements, but considerations of temperature range, mechanical durability and format, along with the physical package surrounding the substrate must also be managed. With a variety of material configurations and circuit format capabilities, the choices become a balancing of options to maximize performance and minimizing cost through Design For Manufacturability (DFM) in the circuit board fabrication. These challenges present the IMS printed board fabricator with material selections and fabrication processes unlike those for other printed board or ceramic applications....
Publisher: The Bergquist Company
Bergquist, now a part of Henkel, supplies thermal-management solutions for electronic applications, serving a variety of industries ranging from automotive to consumer and industrial electronics as well as LED lighting.
Chanhassen, Minnesota, USA
Oct 08, 2015 | Julian A. Montoya, Intel Corporation Hillsboro, Oregon
With the push for ever improving performance on semiconductor component I/O interfaces, semiconductor components are being driven into a realm which makes them more sensitive to electrostatic discharge, potentially increasing in sensitivity by 50% every 3-5 years. Today, the majority of modern day semiconductor components are being designed to meet 250Volts of charge device model sensitivity, and that could decrease to 125Volts in the next 3-5 years, and could again decrease to 50Volts-70Volts in the following 3-5 years. The entire electronics industry must prepare for this challenge....
Publisher: Intel Corporation
Oct 01, 2015 | Lars Bruno and Tord Johnson Ericsson AB and MTEK Consulting AB
Solder paste printing is known to be one of the most difficult processes to quality assure in electronic manufacturing. The challenge increases as the technology development moves toward a mix between large modules and small chip components on large and densely populated printed circuit boards. Having a process for quality assurance of the solder paste print is fast becoming a necessity.
This article describes a method to ensure quality secured data from both solder paste printers and inspection machines in electronic assembly manufacturing. This information should be used as feedback in order to improve the solder paste printing process....
Publisher: Ericsson AB
Sep 23, 2015 | Dick Pang, Weifeng Liu, Anwar Mohammed, Elissa Mckay, Teresita Villavert and Murad Kurwa
A molded interconnect device (MID) is an injection molded thermoplastic substrate which incorporates a conductive circuit pattern and integrates both mechanical and electrical functions. (...) Flip chip bonding of bare die on MID can be employed to fully utilize MID’s advantage in device miniaturization. Compared to the traditional soldering process, thermo-compression bonding with gold stud bumps provides a clear advantage in its fine pitch capability. However, challenges also exist. Few studies have been made on thermocompression bonding on MID substrate, accordingly little information is available on process optimization, material compatibility and bonding reliability. Unlike solder reflow, there is no solder involved and no “self-alignment,” therefore the thermo-compression bonding process is significantly more dependent on the capability of the machine for chip assembly alignment....
Publisher: Flex (Flextronics International)
Sep 17, 2015 | Joseph Fjelstad
RoHS legislated restrictions on the materials used in electronics manufacture have imparted significant challenges on the electronics industry since their introduction in 2006. The greatest impacts have been felt by the mandated elimination of lead from electronic solder followed by the demand for the elimination of haloids from flame retardants used in traditional PCB laminates. In the years which have followed the electronics industry has been beset with a host of new challenges in its effort to comply. Failure mechanisms, both new and old, have surfaced which demand solution and the industry suppliers and manufacturing technologists have worked diligently to remedy those vexing faults through the development of a wide range of new materials and equipment for both board manufacture and assembly, along with modifications to the processes used in the manufacture and assembly of printed circuit boards....
Publisher: Verdant Electronics
Sep 10, 2015 | Kimberly M. White, Ph.D., Daniel De Schryver, Ph.D., and Randy Chaya
A new non-halogen flame retardant has been developed and is useful for a variety of high performance applications. This non-reactive phosphorus-based material satisfies fire safety needs for a broad range of resins including epoxy, polyolefin, and polyamide. The combination of excellent flame retardant efficiency, high thermal stability and exceptional electrical properties is unique to this organophosphorus flame retardant and makes it a breakthrough technology for high speed, high frequency use in fast growing wireless and wired infrastructures. Resin performance data, including formulations with synergists, are presented in this paper....
Publisher: Albemarle Corporation
Sep 03, 2015 | V. Desmaris, S. Shafiee, A. Saleem, A. Johansson and P. Marcoux
While the density of chip-to-chip and chip-to-package component interconnections increases and their size decreases the ease of manufacture and the interconnection reliability are being reduced. This paper will introduce the use of embedded fibers in the interconnections as a means of addressing these issues....
Publisher: Smoltek AB
Aug 27, 2015 | Bob Wettermann, MIT
Ever since there has been a widespread usage of surface mount parts, the trend of continued shrinkage of devices with ever finer pitches has continued to challenge PCB assemblers for the rework of same. Todays' pitches are commonly 0.5 to 0.4mm with packages of tiny outline sizes, 5 -10mm square, making the rework of such devices a challenge. In addition to the handling and inspection challenges comes the board density. Spacing to neighboring components continues to be compressed so the rework techniques should not damage neighboring components....
Publisher: BEST Inc.