Choosing the Best Surface Treatment Process for Your PCB

The selection of a surface treatment process for your PCB is crucial and depends on the type of final assembled components. The chosen process can impact production, assembly, and the ultimate use of the PCB. Here, we will explore five common surface treatment processes to help you make an informed decision.

Hot Air Leveling

Hot air leveling was once a dominant process in PCB surface treatment, with a significant market share in the 1980s. However, its usage has declined over the past decade. Currently, approximately 25%-40% of PCBs utilize hot air leveling. While effective for larger components and wires with ample spacing, hot air leveling is not suitable for higher density PCBs as it may affect the flatness crucial for subsequent assembly. HDI boards, in particular, tend to avoid hot air leveling processes. Despite technological advancements enabling hot air leveling for smaller pitches, its practical application remains limited. Some manufacturers have shifted to organic coating and electroless nickel/immersion gold processes, along with tin and silver immersion processes. The industry’s move towards lead-free practices has further restricted hot air leveling usage, despite the introduction of lead-free alternatives, raising concerns about equipment compatibility.

Organic Coating

Organic coating technology is gaining popularity, currently accounting for about 25%-30% of PCB surface treatments and potentially surpassing hot air leveling in usage. Organic coating is versatile, suitable for low-tech and high-tech PCBs, including single-sided TVs and high-density chip packaging boards. It is particularly favored for BGAs. If your PCB does not have specific requirements for surface connectivity or storage limitations, organic coating may be the ideal surface treatment process for your needs.