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 | 2020-04-01 23:32:29.0
Low temperature solder alloys are preferred for the assembly of temperature-sensitive components and substrates. The alloys in this category are required to reflow between 170 and 200oC soldering temperatures. Lower soldering temperatures result in lower thermal stresses and defects, such as warping during assembly, and permit use of lower cost substrates. Sn-Bi alloys have lower melting temperatures, but some of its performance drawbacks can be seen as deterrent for its use in electronics devices.Here we show that non-eutectic Sn-Bi alloys can be used to improve these properties and further align them with the electronics industry specific needs. The physical properties and drop shock performance of various alloys are evaluated, and their results are analysed in terms of the alloy composition, including Bi content and alloying additions.
Technical Library | 2011-05-05 16:17:34.0
Passives account for a very large part of today’s electronic assemblies. This is particularly true for digital products such as cellular phones, camcorders, and computers. Market pressures for new products with more features, smaller size and lower cost v
Technical Library | 1999-07-21 09:00:55.0
Isotropic conductive adhesives are typically silver filled epoxy resins. Electronics assemblers have evaluated these materials for a variety of unique interconnect applications. The goal is a conductive polymer that exhibits similar reliability and performance to traditional solder while offering the benefits of a polymer structure such as low temperature processing and good thermal stability as well as the ability to bond a variety of substrates.
Technical Library | 2008-06-25 16:11:51.0
Printing technologies provide a simple solution to build electronic circuits on o low cost flexible substrates. Nanocomposites will play important role for developing advanced printable technology. Advanced printing is relatively new technology and need more characterization and optimization for practical applications. In the present paper, we examine the use of nanocomposites or materials in the area of printing technology.
Technical Library | 2013-10-13 10:22:48.0
There are numerous factors which directly affect the conformal coating process to greater or lesser degrees. Those which have major impacts irrespective of the substrate / PCB and assemblies include choice of coating material and method of application. Whether conformal coating boards by dip, robot, batch spray or brush methods the viscosity of the coating is a critical factor in the overall process control.
Technical Library | 2017-04-13 10:57:53.0
Parylene has been used for decades as a barrier layer to protect critical devices and components. The parylene deposition process typically requires an adhesion promotion step to make sure the parylene adheres well to the base substrate. Typical adhesion methods don't work well on Kapton and Polyamide, until VSI Parylene came up with a solution.
Technical Library | 2020-02-18 09:56:24.0
Glob Top, Dam and Fill & Flit Chip Underfill To protect PCBs from damaging outside influences, they are coated with a thin layer of casting resin or protective finish during the conformal coating process. In addition to sealing the entire circuit board, it is possible to pot only sections or individual components on the substrate. Different methods ranging from "glob top" to "dam and fill" and "flip chip underfill" have been developed for this purpose.
Technical Library | 2020-09-02 22:14:36.0
The demand for miniaturization and higher density electronic products has continued steadily for years, and this trend is expected to continue, according to various semiconductor technology and applications roadmaps. The printed circuit board (PCB) must support this trend as the central interconnection of the system. There are several options for fine line circuitry. A typical fine line circuit PCB product using copper foil technology, such as the modified semi-additive process (mSAP), uses a thin base copper layer made by pre-etching. The ultrathin copper foil process (SAP with ultrathin copper foil) is facing a technology limit for the miniaturization due to copper roughness and thickness control. The SAP process using sputtered copper is a solution, but the sputtering process is expensive and has issues with via plating. SAP using electroless copper deposition is another solution, but the process involved is challenged to achieve adequate adhesion and insulation between fine-pitch circuitries. A novel catalyst system--liquid metal ink (LMI)--has been developed that avoids these concerns and promotes a very controlled copper thickness over the substrate, targeting next generation high density interconnect (HDI) to wafer-level packaging substrates and enabling 5-micron level feature sizes. This novel catalyst has a unique feature, high density, and atomic-level deposition. Whereas conventional tin-palladium catalyst systems provide sporadic coverage over the substrate surface, the deposited catalyst covers the entire substrate surface. As a result, the catalyst enables improved uniformity of the copper deposition starting from the initial stage while providing higher adhesion and higher insulation resistance compared to the traditional catalysts used in SAP processes. This article discusses this new catalyst process, which both proposes a typical SAP process using the new catalyst and demonstrates the reliability improvements through a comparison between a new SAP PCB process and a conventional SAP PCB process.
Technical Library | 2023-07-04 17:31:22.0
Conformal Coatings are polymeric materials used to protect circuitry, parts, and related components. They are most commonly used to protect printed circuit boards (PCBs) and electronic devices. However, conformal coatings can be applied to a wide variety of materials, including metal, plastic, silicone, ceramics, glass, and even paper. We use the term "substrate" to refer to an object or material that's been coated with a conformal coating.
