Technical Library | 2013-09-25 20:57:24.0
Conformal coating is an enabling process that allows for the ruggedizing of electronic devices and modules. As the process increases the durability of electronics that are subjected to various end-use environmental conditions, it adds value to the product. While it does add value, consumers and manufacturers expect the electronics to work when subjected to dirt, humidity, moisture, corrosive materials, and various other contaminants. This expectation results in a drive to minimize the cost of the process. The lowest cost of ownership for a conformal coating process occurs by utilizing automated selective conformal coating equipment.
Technical Library | 2022-03-16 19:41:17.0
Creep corrosion occurs in electronics assemblies and it is reminiscent to electromigration but does not require electrical field to drive the reaction. Corrosive elements and moisture must be present for creep corrosion to occur. Sulfur is the most prominent element to cause creep corrosion in environments such as paper mills, rubber manufacturing, mining, cement manufacturing, waste water treatment etc., also including companies and locations nearby such industries. The main part of printed circuit board assembly (PCBA) to be affected is the PCB surface finish. Especially immersion silver is prone to creep corrosion, but it sometimes occurs in NiPd (lead frames), and to a lesser extent in ENIG and OSP surface finishes. As the use of immersion silver is increasing as PCB surface finish and electronics are more and more used in harsh environments, creep corrosion is a growing risk. In this paper we will present the driving forces and mechanisms as well as suitable tests and mitigation strategies against creep corrosion
Technical Library | 2012-09-06 18:19:37.0
First published in the 2012 IPC APEX EXPO technical conference proceedings. Pad Cratering opens circuits. This occurs when the resin crack (fracture) migrates through a copper trace or via. This happens at assembly, in service or during handling. When com
Technical Library | 2020-01-01 17:06:52.0
The majority of electronic failures occur due to thermally induced stresses and strains caused by excessive differences in coefficients of thermal expansion (CTE) across materials.CTE mismatches occur in both 1st and 2nd level interconnects in electronics assemblies. 1st level interconnects connect the die to a substrate. This substrate can be underfilled so there are both global and local CTE mismatches to consider. 2nd level interconnects connect the substrate, or package, to the printed circuit board (PCB). This would be considered a "board level" CTE mismatch. Several stress and strain mitigation techniques exist including the use of conformal coating.
Technical Library | 2014-03-06 19:04:07.0
Over the last few years, there has been an increase in the rate of Head-in-Pillow component soldering defects which interrupts the merger of the BGA/CSP component solder spheres with the molten solder paste during reflow. The issue has occurred across a broad segment of industries including consumer, telecom and military. There are many reasons for this issue such as warpage issues of the component or board, ball co-planarity issues for BGA/CSP components and non-wetting of the component based on contamination or excessive oxidation of the component coating. The issue has been found to occur not only on lead-free soldered assemblies where the increased soldering temperatures may give rise to increase component/board warpage but also on tin-lead soldered assemblies.
Technical Library | 2015-07-16 17:24:23.0
Qualification of electronic hardware from a corrosion resistance standpoint has traditionally relied on stressing the hardware in a variety of environments. Before the development of tests based on mixed flowing gas (MFG), hardware was typically exposed to temperature-humidity cycling. In the pre-1980s era, component feature sizes were relatively large. Corrosion, while it did occur, did not in general degrade reliability. There were rare instances of the data center environments releasing corrosive gases and corroding hardware. One that got a lot of publicity was the corrosion by sulfur-bearing gases given off by data center carpeting. More often, corrosion was due to corrosive flux residues left on as-manufactured printed circuit boards (PCBs) that led to ion migration induced electrical shorting. Ion migration induced failures also occurred inside the PCBs due to poor laminate quality and moisture trapped in the laminate layers.
Technical Library | 2013-01-17 15:34:33.0
The use of an electroless nickel, immersion gold (ENIG) surface finish comes with the inherent potential risk of Black Pad failures that can cause fracture embrittlement at the interface between the solder and the metal pad. As yet, there is no conclusive agreed solution to effectively eliminate Black Pad failures. The case studies presented are intended to add to the understanding of the Black Pad failure mechanism and to identify both the plating and the subsequent assembly processes and conditions that can help to prevent the likelihood of Black Pad occurring.
Technical Library | 2018-02-22 10:56:36.0
As companies start to implement lead free soldering processes, hand soldering and associated techniques have been identified as key functions in the manufacturing process requiring additional research and development. Hand soldering tends to occur at the end of the process line where the circuit board has a high intrinsic value and so correct process control will have a significant affect on manufacturing costs and productivity.This paper discusses the fundamental aspects of the hand soldering process and discusses process adaptation requirements for successful lead free implementation.
Technical Library | 2019-05-24 07:26:39.0
Soldering system vendor SEHO runs a Technology Center in its headquarters in Germany, in which all available machines are exhibited and demonstrated. Additionally, the SEHO Academy provides knowledge as a perfect balance of theory and practical application. In both facilities soldering fume occurs, which has damaging effects on human health, manufacturing equipment and products. That's why the company had installed several air cleaning solutions in terms of fume extraction technology. How and why they take care of clean air is the subject of this article.
Technical Library | 2021-09-15 18:53:20.0
Many printed circuit board assemblies (PCBAs) have relays that are soldered to the PCB. If such an electromechanical component fails, it can cause the whole device to fail, just like any other electronic component. The spectrum of root causes that lead to an increased contact resistance or a complete contact failure is totally different from what usually occurs in the electronics domain. This article provides a detailed analysis of these failures and the corresponding root causes, many of them self-centering.
