Disadvantages include; restricted availability, higher price and this being the one floor finish that requires a two-half course of. Also, if the method is not managed, quality points such as 'Black Pad' could occur.
The deposition equipment may be pricey but the by way of-put is excessive enough to convey the price per sqft to simply above that of OSP. Where Lead-Free HASL loses on PCBs with fantastic pitches, as lead-free and organic, OSP is a wonderful alternative for an inexpensive, environmentally pleasant floor finish for your fine pitches. This surface finish even beats different lead-free options which still use toxic materials in their processes or consume extra power to apply.
Its potential that the copper was exposed to sulfur containing compounds which may create a tarnish fairly rapidly. Some packaging supplies like plastics and paper comprise sulfur and these could create tarnish when in contact with the circuit boards. We are buying circuit boards from China and they are coming in with a tarnished trying finish (they have OSP) and we are having soldering issues.
While slightly dearer then leaded HASL finish, among the many lead-free finishes lead-free HASL is comparatively inexpensive. However, for the reason that utility process is similar to HASL, additionally it is not recommended for these PCBs that contain small distances between BGA and SMTs. High temperatures are additionally required to soften lead-free solder, so it might be bothersome to DIYer’s who don’t have the proper gear. OSP is a cost-effective coating; OSP and HASL are usually the bottom price coating choices. OSP additionally offers a flat, uniform surface essential with fantastic-pitch SMT components are used.
OSP is a permeable coating which slows tarnishing of the underlying copper. Tarnish is usually brought on by air publicity over time, however other compounds besides air can permeate the coating.
The OSP coating process doesn't expose the PCB to excessive utility temperatures as is the case with HASL. The excessive software temperatures related to HASL may warp the PCB and/or crack plated via-holes (PTHs). The ENIG end has traditionally been one of the best fine pitch (flat) floor and lead-free choice world-broad. Benefits to this surface end are; lengthy-term experience/knowledge of the product and glorious shelf life. The typical Nickel thickness is seventy five micro inches and three-5 micro inches of gold.