Printed Circuit Boards (PCBs) are always coated with finishes. It forms a layer between a bare PCB and the components mounted on it. Adding a finish ensures good solderability and also protects the copper circuitry from getting exposed. There are different types of finishes such as immersion Silver, immersion Gold, HASL (Hot Air Solder Leveling), immersion Tin, Electroless Nickel Immersion (ENIG), etc. In this post, we will discuss about PCBs that are coated with immersion silver finish in detail.
A Brief about Immersion Silver Finish
Immersion silver is a type of finish that is applied directly over the copper surface of a PCB. This finish is most commonly used for aluminum wire bonding, metallic dome contacts, and EMI shielding.
Benefits of Immersion Silver Finish
Immersion silver finish is gaining popularity in PCB designs due to its beneficial features. Here are some of the key features that make it a preferred choice of material for finishing:
- It allows solder to spread properly on its surface, thus allowing a better soldering of components.
- Immersion silver is RoHS compliant finish and is environment friendly.
- Compared to Organic Solderability Preservative (OSP) finish, immersion silver finished PCBs have a better resistance to environmental ageing.
- This material finish has a capability to survive multiple reflow.
- It has better electrical properties, flatness, and solder joint strength as compared to that of HASL finish.
- It is not affected by the black-pad interfacial fracture phenomenon.
All these aforementioned beneficial features make Immersion Silver PCB an ideal choice for finish.