Technical Library | 2023-01-06 16:18:23.0
PCB/Substrate Finishing Overview - iNEMI - PCB Surface Finish Overview. Surface Finish deployment ranked by surface area. OSP greatest. Imm Tin. ENIG. Silver. ENEPIG.
Technical Library | 2021-10-20 18:21:06.0
The solderability of the SAC305 alloy in contact with printed circuit boards (PCB) having different surface finishes was examined using the wetting balance method. The study was performed at a temperature of 260 _C on three types of PCBs covered with (1) hot air solder leveling (HASL LF), (2) electroless nickel immersion gold (ENIG), and (3) organic surface protectant (OSP), organic finish, all on Cu substrates and two types of fluxes (EF2202 and RF800). The results showed that the PCB substrate surface finish has a strong effect on the value of both the wetting time t0 and the contact angle h. The shortest wetting time was noted for the OSP finish (t0 = 0.6 s with EF2202 flux and t0 = 0.98 s with RF800 flux), while the ENIG finish showed the longest wetting time (t0 = 1.36 s with EF2202 flux and t0 = 1.55 s with RF800 flux). The h values calculated from the wetting balance tests were as follows: the lowest h of 45_ was formed on HASL LF (EF2202 flux), the highest h of 63_ was noted on the OSP finish, while on the ENIG finish, it was 58_ (EF2202 flux). After the solderability tests, the interface characterization of cross-sectional samples was performed by means of scanning electron microscopy coupled with energy dispersive spectroscopy.
Technical Library | 2015-11-25 14:15:12.0
In this study various printed circuit board surface finishes were evaluated, including: organic solderability preservative (OSP), plasma finish (PF), immersion silver (IAg), electroless nickel / immersion silver (ENIS), electroless nickel / immersion gold hi-phosphorus (ENIG Hi-P), and electroless nickel / electroless palladium / immersion gold (ENEPIG). To verify the performance of PF as a post-treatment option, it was added to IAg, ENIG Hi-P, and ENEPIG to compare with non-treated. A total of nine groups of PCB were evaluated. Each group contains 30 boards, with the exception on ENIS where only 8 boards were available.
Technical Library | 2021-12-29 19:37:20.0
The purpose of this study was to compare the strength of the bond between resin and glass cloth for various composites (laminates) and its dependence on utilized soldering pad surface finishes. Moreover, the impact of surface finish application on the thermomechanical properties of the composites was evaluated. Three different laminates with various thermal endurances were included in the study. Soldering pads were covered with OSP and HASL surface finishes. The strength of the cohesion of the resin upper layer was examined utilizing a newly established method designed for pulling tests.
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 | 2021-07-06 21:13:36.0
The surface finishes commonly used on printed circuit boards (PCBs) have an effect on solder paste performance in the surface mount process. Some surface finishes are non-planar like hot air solder level (HASL) which can lead to inconsistencies in solder paste printing. Other surface finishes are difficult to wet during reflow like organic solderability preservative (OSP). What is the overall effect of surface finish on solder paste performance? Which solder paste is best for each surface finish? It is the goal of this paper to answer these questions.
Technical Library | 2021-04-08 00:30:49.0
As the electronic industry moves to lead-free assembly and finer-pitch circuits, widely used printed wiring board (PWB) finish, SnPb HASL, has been replaced with lead-free and coplanar PWB finishes such as OSP, ImAg, ENIG, and ImSn. While SnPb HASL offers excellent corrosion protection of the underlying copper due to its thick coating and inherent corrosion resistance, the lead-free board finishes provide reduced corrosion protection to the underlying copper due to their very thin coating. For ImAg, the coating material itself can also corrode in more aggressive environments. This is an issue for products deployed in environments with high levels of sulfur containing pollutants encountered in the current global market. In those corrosive environments, creep corrosion has been observed and led to product failures in very short service life (1-5 years). Creep corrosion failures within one year of product deployment have also been reported. This has prompted an industry-wide effort to understand creep corrosion
Technical Library | 2023-04-25 22:03:25.0
This report hopes to achieve several goals: 1. Determine the link between bare PWB contamination, soldered assembly contamination and long-term product reliability. 2. Establish measurable limits for bare PWB cleanliness as well as process control limits for both an aqueous as well as a water-soluble soldering process. 3. Determine whether there is any correlation between common, industry-accepted rose/modified rose (omegameter/ionograph type) testing and long term product reliability. 4. Determine the effect PWB plating finish (HASL, Immersion Silver and Cu OSP) has on both bare PWB contamination as well as soldered assembly in a no clean and water soluble process. 5. Determine whether there is a link between percentage of saponifier used to wash soldered assemblies and long-term reliability. 6. Establish a more cost-effective test for manufacturers to use as a process-monitoring tool.
Technical Library | 2021-07-06 21:18:02.0
A new PCB surface finish has been developed that offers outstanding performance and excellent environmental protection. This finish has the potential to replace more common finishes such as ENIG, ImAg, ImSn, ENEPIG, or OSP with a chemically resistant plasma deposited coating. The substitution of the wet processes with this dry plasma process offers significant advantages e.g. lower quantities of chemicals used, environmental benefits and improved operator safety.
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.
