Immersion Tin PCBs

Immersion Tin is the least expensive of all types of coatings. It is very economical; however, it does come with certain shortcomings. One of the main drawbacks of immersion Tin is, once you deposit the tin onto copper, it will begin to tarnish. This also means if you wish to avoid low quality solder joints, it is imperative to do your soldering activity within 30 days. Below are advantages and disadvantages of immersion tin surface finish.

HASL

Lead-Free HASL is similar to standard HASL, but with an obvious difference… It doesn’t use Tin-Lead solder. Instead, Tin-Copper, Tin-Nickel or Tin-Copper-Nickel Germanium may be used. This makes Lead-Free HASL an economical and RoHS compliant choice. But like standard HASL it is not ideal for smaller components.

Immersion Silver

Immersion silver is a non-electrolytic chemical finish applied by immersing the copper PCB into a tank of silver ions. It is a good choice finish for circuit boards with EMI shieldingand is also used for dome contacts and wire bonding. The average surface thickness of the silver is 5-18 microinches.

Comparison With These Surface Finishes

·The features of immersion silver as surface finish place it in between OSP and immersion gold. Even when exposed to humidity, heat, and pollution, immersion silver continues to provide good solderability and electrical connection, although it will tarnish. Immersion gold has a layer of nickel under it, which provides it with physical strength. As there is no nickel layer under immersion silver, its physical strength is lower than that of immersion gold.

·Immersion silver requires more care for storage and handling than immersion tin does. However, immersion silver is safer for the environment than immersion tin is.

·Immersion silver is easier to use compared to Organic Solder Preservative or OSP is.

·Immersion silver offers a more planar surface than HASL does.

It is important to select the appropriate surface finish for your project by considering the various options while factoring in performance requirements and material costs.

• 1. What is immersion tin?

  Immersion Tin is a chemical process which applies a very thin layer of tin to the copper. It is not used as often as other finishes because there are many other alternatives and not all printed circuit board manufacturers offer it.

• 2. How thick is immersion tin?

  Immersion Tin is the lead-free alternative to the Hot Air Levelling process. An extremely finely textured tin layer with a thickness between 0.7 μm and 1 μm is applied to the circuit board surface and into the bore holes.

• 3. What is tinning process in PCB?

  PCB tinning is the process of coating copper traces with layers of tin, preventing it from any possible degradation, oxidation, or corrosion. The tin plating will also help mask copper traces while the circuit board is being etched.

• 4. What is the difference between HASL and immersion tin?

  HASL is usually made of tin alloy, which is divided into lead and lead-free. Immersion tin is made of tin salt and is formulated into an acidic solution containing tin.

• 5. Why is immersion tin used?

  Immersion tin is a lead-free surface finish, which is highly desirable in today’s age. This is the ultimate surface finish for fine pitch surface mount components due to its ability to give a flat, thin, and smooth surface for PCB assembly.

Get custom Immersion Tin PCB that authenticates your business products and makes it an element for quick turnaround at a first go! At VictoryPCB, we work with each customer to ensure they get the boards they need, the way they need them. Contact us today for a quote for your specifications.