Technical Library | 2019-06-06 00:19:02.0
More and more people and things are using electronic devices to communicate. Subsequently, many electronic products, in particular mobile base stations and core network nodes, need to handle enormous amounts of data per second. One important link in this communication chain is high speed pressfit connectors that are often used to connect mother boards and back planes in core network nodes. These new high speed pressfit connectors have several hundreds of thin, short and weak pins that are prone to damage. Small variations in via hole dimensions or hole plating thickness affect the connections; if the holes are too small, the pins may be bentor permanently deformed and if the holes are too large they will not form gas tight connections.The goal of this project was to understand how rework of these new high speed pressfit connectors affects connection strengths, hole wall deformations and plating cracks.
Technical Library | 2016-01-08 11:56:03.0
Solder joint encapsulant adhesives have been successfully used to enhance the strength of solder joints and improve thermal cycling as well as drop performance in finished products. The use of solder joint encapsulant adhesives can eliminate the need for underfill materials and the underfill process altogether, thus simplifying rework, which results in a lower cost of ownership.Solder joint encapsulant adhesives include: low temperature and high temperature solder joint encapsulant adhesives, and their derivatives. Each solder joint encapsulant adhesive has: unfilled and filled solder joint encapsulant adhesives, and solder joint encapsulant paste. Each solder joint encapsulant product has been designed for different applications. In this paper, we are going to discuss the details and future of solder joint encapsulant adhesives.
Technical Library | 2013-01-09 18:31:54.0
The increased temperatures associated with lead free processes have produced significant challenges for PWB laminates. Newly developed laminates have different curing processes, are commonly filled with ceramic particles or micro-clays and can have higher Tg values. These changes designed to reduce Z-axis expansion and improve the materials resistance to thermal excursions through primary attach and rework operations have also produced harder resin systems with reduced fracture toughness.
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 | 2024-09-02 17:31:09.0
The cracking and delamination of printed circuit boards (PCB) during exposure to elevated thermal exposure, such as reflow and rework, have always been a concern for the electronics industry. However, with the increasing spread of Pb-free assembly into industries with lower volume and higher complexity, the occurrence of these events is increasing in frequency. Several telecom and enterprise original equipment manufacturers (OEMs) have reported that the robustness of their PCBs is their number one concern during the transition from SnPb to Pb-free product. Cracking and delamination within PCBs can be cohesive or adhesive in nature and can occur within the weave, along the weave, or at the copper/epoxy interface (see Figure 1). The particular role of moisture absorption and other PCB material properties, such as out of plane expansion on this phenomenon is still being debated.
Technical Library | 2012-12-20 14:36:09.0
The increased function of personal electronic devices, such as mobile phones and personal music devices, has driven the need for smaller and smaller active and passive components. This trend toward miniaturization, occurring at the same time as the conversion to RoHS-compliant lead-free assembly, has been a considerable challenge to the electronics assembly industry. The main reason for this is the higher reflow process temperatures required for Pb-free assembly. These higher temperatures can thermally damage the PCB and the components. In addition, the higher reflow temperatures can negatively affect the solder joint quality, especially when coupled with the smaller paste deposits required for these smaller components. If additional thermal processing is required, the risk increases even more. First Published at SMTA's International Conference on Soldering and Reliability in Toronto, May 2011
.gif)
