Technical Library | 2023-09-13 12:48:06.0
PCB cleaning machines are essential for ensuring the quality and reliability of printed circuit boards (PCBs). These machines remove contaminants and debris from PCBs, which can cause defects and reliability issues.
Technical Library | 2021-03-10 23:57:29.0
Latent short circuit failures have been observed during testing of Printed Circuit Boards (PCB) for power distribution of spacecraft of the European Space Agency. Root cause analysis indicates that foreign fibers may have contaminated the PCB laminate. These fibers can provide a pathway for electromigration if they bridge the clearance between nets of different potential in the presence of humidity attracted by the hygroscopic laminate resin. PCB manufacturers report poor yield caused by contamination embedded in laminate. Inspections show ...
Technical Library | 2023-01-06 16:09:03.0
The 4-14 IPC Standards Committee recently created a revision to the IPC4552 specification for Electroless Nickel/Immersion Gold (ENIG) finished Printed Circuit Boards (PCB). Revision A brings a more comprehensive evaluation of metal layer thicknesses measurement, composition and introduces, for the first time, a quality aspect for nickel corrosion which has been historically connected to a defect called black line nickel or black pad.
Technical Library | 2016-09-06 04:54:27.0
Printed circuit boards are the base of electronic products in a variety of consumer and industrial applications. New PCBs always perform well. However, their performance will deteriorate with time due to exposure to different environmental conditions like condensation, moisture, contamination of the iconic material on the surface, dust and dirt, mildew, alpha particles, etc. To avoid these problems, PCBs are protected with conformal coatings. Let’s see how this is done, and how they protect PCB components.
Technical Library | 2018-05-09 22:15:29.0
Creep corrosion on printed circuit boards (PCBs) is the corrosion of copper metallization and the spreading of the copper corrosion products across the PCB surfaces to the extent that they may electrically short circuit neighboring features on the PCB. The iNEMI technical subcommittee on creep corrosion has developed a flowers-of-sulfur (FOS) based test that is sufficiently well developed for consideration as an industry standard qualification test for creep corrosion. This paper will address the important question of how relative humidity affects creep corrosion. A creep corrosion tendency that is inversely proportional to relative humidity may allow data center administrators to eliminate creep corrosion simply by controlling the relative humidity in the data center,thus, avoiding the high cost of gas-phase filtration of gaseous contamination. The creep corrosion relative humidity dependence will be studied using a modified version of the iNEMI FOS test chamber. The design modification allows the achievement of relative humidity as low as 15% in the presence of the chlorine-releasing bleach aqueous solution. The paper will report on the dependence of creep corrosion on humidity in the 15 to 80% relative humidity range by testing ENIG (gold on electroless nickel), ImAg (immersion silver) and OSP (organic surface preservative) finished PCBs, soldered with organic acid flux.
Technical Library | 2020-09-02 22:02:13.0
With the adoption of Wafer Level Packages (WLP) in the latest generation mobile handsets, the Printed Circuit Board (PCB) industry has also seen the initial steps of High Density Interconnect (HDI) products migrating away from the current subtractive processes towards a more technically adept technique, based on an advanced modified Semi Additive Process (amSAP). This pattern plate process enables line and space features in the region of 20um to be produced, in combination with fully filled, laser formed microvias. However, in order to achieve these process demands, a step change in the performance of the chemical processes used for metallization of the microvia is essential. In the electroless Copper process, the critical activator step often risks cross contamination by the preceding chemistries. Such events can lead to uncontrolled buildup of Palladium rich residues on the panel surface, which can subsequently inhibit etching and lead to short circuits between the final traces. In addition, with more demands being placed on the microvia, the need for a high uniformity Copper layer has become paramount, unfortunately, as microvia shape is often far from ideal, the deposition or "throw" characteristics of the Copper bath itself are also of critical importance. This "high throwing power" is influential elsewhere in the amSAP technique, as it leads to a thinner surface Copper layer, which aids the etching process and enables the ultra-fine features being demanded by today's high end PCB applications. This paper discusses the performance of an electroless Copper plating process that has been developed to satisfy the needs of challenging amSAP applications. Through the use of a radical predip chemistry, the formation, build up and deposition of uncontrolled Pd residues arising from activator contamination has been virtually eradicated. With the adoption of a high throwing power Copper bath, sub 30um features are enabled and microvia coverage is shown to be greatly improved, even in complex via shapes which would otherwise suffer from uneven coverage and risk premature failure in service. Through a mixture of development and production data, this paper aims to highlight the benefits and robust performance of the new electroless Copper process for amSAP applications
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