PCB Surface Finishes- Understanding the Basics

The demand for electronics and electronic products has been increasing unceasingly for quite some years. The graph of demand is consistently on rise as newer technologies are being introduced. This demand is driving the scope of the electronics industry, and more particularly, the printed circuit boards (PCBs).

The copper layer present on the circuit boards, when exposed to the atmosphere, undergoes oxidation, and thus deteriorate. This can cause the circuit boards to become non-functional, thus losing their value, and use. Thus, a protective layer is required to prevent the oxidation phenomenon. This is where the surface finishes come into the picture. In this post, we will discuss the right use of surface finish, and their various types.

PCB Surface Finishes

What Are Surface Finishes?

A surface finish is a layer of coating, which is applied on the printed circuit board to protect it from corrosion, or oxidation. Besides this, the layer also enhances the overall look of the PCB. This layer acts as an interface between the printed circuit board, and the components mounted on the board. In addition to this, the finish is responsible to provide a solderable surface to solder different components on the PCB. This helps enhance the electric performance, and thus increase the reliability of the printed circuit board significantly.

How to Be Sure That You Select the Right Surface Finish?

There are several types of PCB surface finishes, and this can make it a bit tricky to choose the right type. Although the main objective of all the finish types is to protect the PCB from oxidation, still, each type has its own set of properties, advantages, and disadvantages. This can make the selection process confusing for those, who are not that acquainted with the finish options. In such cases, you can refer to the following set of factors, which can help you in selecting the right surface finish:

  • First of all understand why the finish is needed.
  • Determine whether the board requires lead / lead-free surface finishing.
  • Identify the pitch, as well as the type of components that will be place on the printed circuit board.
  • Identify the handling and environmental issues that will be faced by the final end product.
  • Do a proper comparison of different types of surface finishes before you round up on one.
  • Determine the required resistivity of the printed circuit board.

What are the Different Types of PCB Surface Finishes Used?

Based on the materials used, there is a wide variety of surface finish options available today. Some most commonly used types of surface finishes, include:

  • HASL (Hot Air Solder Leveling) / Lead Free HASL
  • OSP (Organic Solderability Preservative)
  • Immersion Tin
  • ENIG (Electroless Nickel Immersion Gold)
  • Hard Gold
  • Immersion Gold
  • Immersion Silver

Indeed, the surface finish plays a vital role in protecting the circuit boards from becoming inoperable. Thus, it is said that a printed circuit boards, which does not have a surface finish is incomplete. It is only after adding the layer of a proper finish, one can say that the PCB manufacturing is properly done. In this post, we discussed about the basics or surface finishes, their types, and how to select the proper finish based on your application requirements. In the upcoming posts will be discussing in detail the different types of surface finishes, and their advantages. So, stay tuned and keep watching this space.

PCB Online Quote