Understanding the Pros and Cons of OSP Surface Finishing in PCBs

As a comprehensive PCBA manufacturer, we aim to shed light on the significance and nuances of OSP (Organic Solderability Preservatives) surface finishing in PCB manufacturing. OSP, or Organic Solderability Preservatives, also known as Copper Protective Agent, is a widely-used surface treatment method that shields exposed copper from air during PCB fabrication. However, as with any technology, OSP comes with its own set of strengths and limitations. Let’s explore the advantages and disadvantages of this surface treatment technique in PCBA.

Advantages of OSP:

OSP serves as a protective barrier between copper and air. Its organic nature sets it apart, making it a cost-effective alternative compared to other treatments like tin-spraying processes. The principle involves chemically cultivating a thin organic film on a clean bare copper surface, often found in computer motherboards.

However, there are drawbacks to consider:

OSP’s transparency and lack of color make visual inspection challenging; distinguishing whether OSP treatment has been applied becomes difficult.

OSP’s non-conductive nature interferes with electrical testing, necessitating the removal of the OSP layer using tin paste via stencil printing to facilitate these tests.

OSP is susceptible to corrosion and vulnerable to acid and temperature influences. Prolonged storage or exposure can require re-surface treatment.

An OSP-treated board exposed to air for around ten days becomes unsuitable for component soldering.

This insight provides an overview of OSP surface treatment’s roles and its pros and cons in PCB fabrication. For deeper insights, don’t hesitate to get in touch with MTI PCBA.