Flexible Printed Circuit Board Surface Finishes

PCB Plating Finishes

Groundbreaking thought processes and PCB designs – is A-flex in a nutshell. As an electronics company, we understand the need to be current. Your designs, your thought processes, and pretty much anything to do with your business, needs to be current. This is the only way to stay relevant, and be able to sell anything. We help our clients embrace new technologies and improve their overall business efficiency.

When fabricating your PCBs, several decisions are made regarding the materials and technologies used. One of the most important decisions is choosing the right surface finish. We provide some of the best surface finishes for PCBs. Every finish material has its pros and cons. We provide our clients finish options that complement the functionality and environment of the application. The surface finish should be chosen in a way that improves product performance.

finshed flexible PCB

Types of PCB Surface Finishes

The application environment, functionality requirements of the PCB, and several such factors will determine the type of surface finish used on your PCB.

  • ENIG (Electroless Nickel/ Immersion Gold)
  • This is the most commonly used surface finish. It is popular because it doesn’t tarnish, is long-lasting, and reliable. In this process, the board is first coated with nickel and then a thin layer of gold is applied. The gold protects the nickel from corroding. Although this is a lead-free option, it is not as economical as immersion silver. It could also pose problems during the soldering process.

    Surface Thickness: 78 – 80 micro inches (75 micro inches of nickel and 3-5 micro inches of gold).

    The following options for the gold layer are available:

    Gold Flash: 5 – 15 micro inches
    Full Body Gold: 30 – 60 micro inches
    Selective Gold: 30 – 50 micro inches
    Bondable Gold: 30 – 80 micro inches

    Shelf Life: 12+ Months

  • Immersion Silver

    Because of the impending legislation for lead-free PCBs, immersion silver is gaining popularity. As a finish material, silver is compatible with various types of assemblies. Its increasing popularity is making the material readily available, thus reducing and stabilizing its cost.

    Surface Thickness: 5-12 micro inches
    Shelf Life: 12 Months

  • Immersion Tin

    This process is also widely used by many manufacturers. Immersion tin offers an even finish. The only drawback is its short life span. However, it makes up for this with high performance and low price.

    Surface Thickness: 20-40 micro inches
    Shelf Life: 3-6 Months

  • HASL (Hot Air Solder Leveling)

    This process has been the industry standard for decades. The tin-lead process is widely used in applications where usage of lead is not a concern. However, this process and materials used have been modified to be used in lead-free applications.

    1. Sn/ Pb HASL: This process ensures fast turnaround times, longevity, and cost-effectiveness.

      Surface Thickness: 30-1500 micro inches
      Shelf Life: 12+ Months

    2. Lead-Free HASL: Lead free alloys like Sn/Cu/Ni/Ge or Sn/Ag/Cu (SAC) are used in this process. All the equipment used for component mounting should be lead-free.

      Surface Thickness: 300 -1000 micro inches
      Shelf Life: 12 Months

  • OSP (Organic Solderability Preservatives)

    Invented in the 1970’s, this is one of the oldest processes in place. Since then, it has undergone several modifications leading to improved functionality. This finish is now cost-effective, has excellent co-planarity features, is compatible with multiple assemblies, and can be soldered easily.

    Surface Thickness: Almost Immeasurable
    Shelf Life: 6-12 Months (Needs to be stored in specific conditions)

    Our designs and products are developed in response to the needs of several industries. We keep innovating and changing our offerings in accordance with the specific changes taking place in the design of critical products in every industry. This makes it easier for organizations to integrate newer technologies into their systems and applications. This is helpful not only to be complaint with the latest rules and regulations but also to appeal to customers following current innovations and market trends.

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