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 | 2012-12-13 21:20:05.0
First published in the 2012 IPC APEX EXPO technical conference proceedings. We investigated the micro-void formation of solder joints after reliability tests such as preconditioning (precon) and thermal cycle (TC) by varying the thickness of Palladium (Pd) in Electroless Nickel / Electroless Palladium / Immersion Gold (ENEPIG) surface finish. We used lead-free solder of Sn-1.2Ag-0.5Cu-Ni (LF35). We found multiple micro-voids of less than 10 µm line up within or above the intermetallic compound (IMC) layer. The number of micro-voids increased with the palladium (Pd) layer thickness. Our results revealed that the micro-void formation should be related to (Pd, Ni)Sn4 phase resulted from thick Pd layer. We propose that micro-voids may form due to either entrapping of volatile gas by (Pd, Ni)Sn4 or creeping of (Pd, Ni)Sn4.
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.
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Auspi Enterprises Co., Ltd., one of the professional suppliers of printed circuits in China. We found your company info on the web knowing that you're dealing with electronics, which we think you may have demand on pcbs.
Industry News | 2016-08-19 05:00:52.0
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Industry News | 2010-05-05 23:20:11.0
Niedernhall – PCB specialist Würth Elektronik once again demonstrates its competence in system solutions and customer support; now offering one-stop flex-rigid PCB solutions with ZIF contacts and custom designed ZIF connectors.
Electronics Forum | Wed Aug 11 18:36:03 EDT 2004 | davef
90 Knoop. Q2: Thickness is 4 to 10 u" for Au and 300 to 400 u" for nickel A2: This looks like a ENIG spec. Although, the Ni is quite heavy, 150 uin is sufficient for most applications. [IPC-4552 ENIG specification: * Gold thickness of 0.075 - 0.125
Electronics Forum | Wed Aug 05 07:46:46 EDT 1998 | Earl Moon
| We have mixed to negative feelings about Omikron, but I beileve it is due to problems with the board fabricator rather than the process itself. When done properly, our Omikron boards have had very good solderability. However, we have had several
Electronics Forum | Tue Dec 01 07:24:44 EST 1998 | Earl Moon
| Hi folks , | Lately we are seeing a lot of rawcards with black spots on the pads - most of them have Au finish(immersion gold) . We did a lot of inspecton after wave solder and found that only (fine pitch) QFP are affected the most. Our inspection
Electronics Forum | Tue Dec 01 07:54:49 EST 1998 | kallol chakraborty
| | Hi folks , | | Lately we are seeing a lot of rawcards with black spots on the pads - most of them have Au finish(immersion gold) . We did a lot of inspecton after wave solder and found that only (fine pitch) QFP are affected the most. Our inspec
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