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Immersion TIN PCB

  • Over 10 years’ experience
  • Competitive price
  • Excellent Quality Immersion PCB
  • Wide range of Immersion

Features of Immersion Tin

1.1  Baked at 155 for 4 hours (i.e., equivalent to a year of storage), or after 8 days of high temperature and high humidity test (45, 93% relative humidity), or after three reflow soldering still has excellent solderability.

1.2  Sink tin layer smooth, flat, dense, more difficult to form copper-tin metal interdigitates than electroplated tin, sink tin layer thickness up to 0.8-1.5μm, can withstand multiple lead-free soldering impact.

1.3  Stable solution, simple process, can be used continuously by analysis of the replenishment, no need to change the cylinder,suitable for both vertical and horizontal processes. The cost of sinking tin is lower than nickel gold.

1.4  Suitable for fine line high density IC package hard board and flexible board,suitable for surface mount (SMT) or press-fit (Press-fit) mounting process.Lead-free and fluorine-free, no pollution to the environment, free recycling of waste liquid.

immersion-tin-pcb-1
immersion-tin-pcb

Factors affect the tin sinking rate?

Tin concentration: The settling rate of tin increases with the increase of tin concentration. The appearance of settling layer does not change with increasing tin concentration, so increasing tin concentration can effectively improve settling rate.

Influence of organic sulfonic acid concentration: The sedimentation rate of tin increases with the increase of organic sulfonic acid concentration. The rate remained constant when the organic sulfonic acid content exceeded 110g/L, but when the organic sulfonic acid concentration was below 50ml/L, the tin layer formed would fog.

Effect of thiourea concentration: The rate of tin deposition increases with the increase of thiourea concentration. If the thiourea density up then 250g/L, the appearance of the tin layer becomes rough and foggy.

Temperature: During the range of 40℃ ~ 80℃, the deposition rate of tin increases as temperature rising.The thickness of tin layer increases with time, but stabilizes after 20 minutes at 60℃. Therefore, in production, choose 60℃ for 10-12 minutes, can get 1.5μm thick tin layer.

What need to pay much attention when do Immersion Tin pcb?

The coating requires a precise handle – gloves should be used when assembling. Corrosion may occur when making soldermask jumpers (less than 5 mm). Plugging the holes on one side, using a stripping mask and leaded solder is not recommended during application.

Unlike sink gold/sink silver, sink tin is less common and is rarely used in the production of printed circuit boards. In addition, this surface treatment can lead to an increase in intermetallic compounds and short circuits in the landing area associated with whiskers.

immersion-tin-pcb-3

 

Immersion Tin PCB

Venture immersion tin PCB is also known as White Tin and is a chemical process. We offer immersion tin PCB which applies a very thin layer of tin to the copper.

The Venture immersion tin PCB is widely used as an alternative to a lead-based surface finish. If you are looking for a professional designer of immersion tin PCB, Venture is always a good choice. We offer high-end immersion tin PCB better for your project.

 

Trusted Immersion Tin PCB Manufacturer and Supplier in China

Immersion Tin PCB

Venture Electronics offers different types of finishes such as immersion tin PCB to suit your project types. Venture Electronics is the perfect place to ease your worries with zero stress.

Venture immersion tin PCB is a type of metallic finish used directly over the printed circuit board metal. We design immersion tin PCB to prevent the oxidation of the underlying copper.

Our immersion Tin PCB has good storage life to offer. We offer immersion Tin PCB with some advantages:

  • immersion tin is re-workable
  • highly suitable for press fit pin insertion
  • has no lead
  • ensures a flat surface

Venture immersion Tin PCB does require careful handling during the PCB Assembly Process. Our immersion Tin PCB comes with a smooth and very flat finish. It makes ideal for fine pitched surface mount components that will be placed on the circuit board.

We can also offer sustainability immersion Tin PCB.

Venture Electronics is a professional designer of immersion Tin PCB for more than 10 years. We have different types of surface finish that can be used along with your type of project.

Aside from immersion Tin PCB, we also offer Immersion Silver PCB, OSP PCB, Enig PCB, and many more.

As a professional manufacturer, Venture can provide you the best solution for your immersion Tin PCB requirements. You can find a full variety of Immersion Tin PCB at Venture.

Most of the technical industries around the world have relied on us. Make Venture Electronics as your top supplier of immersion tin PCB now.

Contact us now for more information about our immersion tin PCB, we will respond to you right away!

Immersion Tin PCB:  The Ultimate FAQ Guide

Immersion-Tin-PCB-The-Ultimate-FAQ-Guide

Today, I am going to answer all questions you have been asking about another PCB surface finish – immersion Tin PCB.

Through this guide, you will know whether immersion Tin PCB is suitable for you or not.

Let’s dive right in.

What is Immersion Tin PCB?

These are printed circuit board whose copper pads have a Tin layer.

Normally, you will use the Tin layer to protect the PCB from oxidation.

Immersion Tin PCB

Immersion Tin PCB

It is one of the lead-free alternatives available in the electronics industry.

This type of board offers a good flat surface for soldering PCB components.

Therefore, it is suitable for diverse market segments.

Some of which are communication, automotive, consumers, and industrial electronics.

What is Immersion Tin Plating?

It yields a thin consistent tin layer on the copper surface of a PCB.

You can achieve it by bathing your PCB in an electroless chemical solution.

The intention is to protect the copper layer from oxidation during storage.

As a result, it extends the PCB’s shelf life.

The tin layer usually appears whitish after the plating process.

A reason for its alternative name ‘White Tin’.

This process is the most cost-effective among the immersion surface finish methods.

It is RoHS compliant with excellent planarity providing you with a good workable surface when assembling components.

What are the Advantages of Immersion Tin PCB?

There are some benefits that you will realize when using this plating method.

Some of them are;

  • It is Lead-free – This makes it a good choice when fabricating consumer electronics that require RoHS compliance.
  • Its superb flat surface gives you a compatible working surface when soldering fine pitched/ BGA surface mount components.
  • It is a cost-effective method due to the affordable materials you use and the easy process steps.
  • It offers a chance for re-works in case you experience an error during the soldering process.
  • You can keep it under storage for a period of 6 months.
  • It still provides you with a good solderable surface even after you expose it to several thermal cycles.
  • It is also reliable when using press-fit pin insertion to develop backplane panels.

What are the Disadvantages of Immersion Tin PCB?

Some drawbacks are associated with this type of PCB finish.

Some of which are;

  • When you store it for a long period; the tin might end up losing its solderability.

This is because both tin and copper have a strong affinity causing diffusion of one metal into the other.

Therefore, you need to store it for a short time only.

  • It is highly sensitive to handling.

Touching it with bare hands can cause tarnishing of the surface.

This demands you to always use protective gloves.

  • Tin whiskers are likely to arise when using this finish.

They cause shorting problems that affect the PCB’s performance and durability.

  • The use of thiourea in the immersion process causes a health concern as it is a carcinogenic substance.
  • This finish is not ideal when your board design contains incorporates plated through holes.
  • At times, you may subject it to baking before use.

Normally, this is an important process that drives out moisture.

However, this process may lead to a negative effect.

  • Using peelable masks is a challenge where you apply this coating.
  • It is also difficult to measure the tin’s thickness on your board.
  • The tin surface cannot stand multiple reflow or assembly processes.
  • When making contact switch designs, this finish is not a suitable option.
  • The solder mask foil demands high requirements because this plating is quite aggressive to it.

Why is Immersion Tin used?

You can use this surface plating as a good substitute for a lead-based surface finish.

If you intend to work with fine pitch or BGA surface mount components, then this finish is ideal.

It will give you a consistently flat and smooth surface for the assembly of PCB components.

Additionally, this method guarantees you of sustainability.

It further utilizes fewer amounts of water and chemicals during the application process.

This makes it a more economical process than other immersion finishes.

Having a Tin layer on your PCB also makes re-working possible.

You can easily make repairs in case you experience any sort of defects when soldering components.

What Process is used to Apply Immersion Tin?

To come up with a Tin layer on your PCB you will require to use an autocatalytic chemical reduction process.

You can achieve this using a liquid bath that contains Tin cations.

This reaction process deposits a consistent and thin Tin coating on the PCB’s copper traces.

Its thickness is approximately 0.7 to 1.0 microns.

You should also adhere to the correct requirements of temperature, time, and bath composition to make the process successful.

Which Products are Ideal for Immersion Tin Surface Finish?

Several products go well with this type of finish.

Some of them are;

  • HDI boards
  • Fine pitch components and micro vias
  • Press-fit applications

What are Tin Whiskers?

These are electrically conductive, very thin crystalline structures, that emerge from the surface of a PCB with immersion tin finish.

They can grow to a length that exceeds 10mm.

One of their major effects is the cause of short circuits which leads to circuit or system failure.

These growths develop links between circuit elements that are closely spaced causing a damaging effect on the PCB’s performance.

This leads to a major hindrance when operating electronic appliances

Several theories try to suggest the occurrence of tin whiskers.

Some say that their growth is as a result of relieving compressive stress in the tin plating.

Others claim that their protruding is as a result of recrystallization and abnormal tin grain growth processes.

Additional factors such as pressure, moisture, temperature, thermal cycles contribute to their growth.

What are the Main Identifiers that Validate Tin Whiskers?

Several factors can help you to distinguish the occurrence of this phenomenon.

They include;

  • Shape – Their appearance may be straight, forked, hooked, or kinked.
  • Length – They may grow to different lengths ranging from a few mm up to 10mm.
  • Growth time – For them to become visible, they can take some days or even a year in some instances.

Can you avoid Tin Whiskers? How?

Yes, it is possible.

There are some ways through which you can avoid the existence of tin whiskers.

One of the main solutions is to avoid using pure tin and instead use a tin alloy when plating.

You can as well take the following measures to inhibit their growth;

On the PCB;

  • Do not use Tin on the copper traces.
  • Use an alternative surface finish such as electroless nickel immersion gold (ENIG), immersion silver, or nickel.
  • For the solder pads, consider treating them with ENIG, immersion silver, or nickel.

For Components;

  • To prevent mechanical stress, consider using flat integrated circuit packaging.
  • Use terminals that are plated with gold, silver, or nickel.

During the Soldering Process;

  • You can use an alloy of tin, silver, and copper as the solder.
  • Consider using a matt finish in case you use a pure tin solder.
  • After soldering, expose your PCB to temperatures of 150 °C for one hour. This is done to get rid of internal stresses within the tin surface.

What can Immersion Tin PCB offer?

Apart from sustainability, this type of surface finish offers:

Immersion Tin PCB

Immersion Tin PCB

  • Good surface planarity is ideal for assembling components.
  • Excellent flexibility especially for fine pitch boards.
  • Few press-fit requirements for boards that utilize thick substrates.
  • A production process that utilizes less power and water.

What is the Specification for Immersion Tin Plating for PCBs?

Immersion Tin Plating

Immersion Tin Plating

IPC-4554

This guideline elaborates on the requirements for the use of this type of finish method on printed circuit boards.

The supplier, manufacturer, contract manufacturer, and original equipment manufacturer can use it.

How does Immersion Tin compare to Immersion Silver Surface Finish?

These two types of PCB surface finish compare in different ways;

  • Immersion tin has a shorter shelf life than immersion silver.

You can keep it under storage for up to 6 months while immersion silver can last for 12 months.

  • Immersion tin is less environmentally safe than immersion silver.

This is because it incorporates Thiourea (a carcinogen) during its process.

  • Immersion tin is more cost-effective when you compare it to immersion silver.

This is due to its consumption of less water and power when processing.

  • Immersion tin cannot survive multiple reflows and assembly processes.

This is possible for boards with immersion silver.

  • You also require putting on protective gloves when handling both immersion tin and immersion silver because fingerprints can cause tarnishing.
  • Immersion tin reacts with copper due to the high affinity of copper and tin metal.

This causes the tin to diffuse into copper making the surface lose its solderability and last for a short period.

On the other hand, immersion silver does not react with copper enabling it to last longer.

  • Like immersion tin, immersion silver is also prone to whiskering.

This makes them experience short circuits when the whiskers protrude.

  • Both immersion silver and immersion tin require stringent storage conditions.

They can tarnish easily when you expose them to air.

  • Immersion silver and immersion tin are also free from getting black pads.

What are the Main PCB Features that Influence the Selection of Immersion tin PCB?

There are several attributes that you need to consider when choosing this type of surface finish for your PCB.

They consist of;

  • Cost – This surface finish saves on cost.

It is more economical when you compare it to other immersion coatings.

  • Volume – When you intend to produce a high volume of PCBs, then this finish is suitable for you.
  • Cosmetics – This plating process yields a white surface finish on your PCB.
  • Fine pitch components – In case you plan to use a high number of components, using this surface finish makes it compatible.
  • Shock drop – For components that possess a concern for brittle fractures, a tin-copper bond provides good strength.
  • Corrosion environment – This surface finish can withstand creep corrosion.

Why is Immersion Tin PCB sometimes not recommended?

The prevalent factor that makes this surface finish not ideal for use, is the incorporation of Thiourea in its process.

This compound has the potential to cause cancer when people come into contact with it.

It places fabricators and end-users of electronics made with this finish at risk.

Immersion Tin PCB

Immersion Tin PCB

What is the Shelf-life of Immersion Tin PCB?

You can keep PCBs with this surface coating under storage for 3 – 6 months before you use it.

If it passes this period, it becomes difficult to solder components leading to low-quality solder joints.

However, to achieve the best results, you should conduct component assembly within 30 days.

What is Immersion Tin PCB Thickness?

The typical thickness of the Tin layer in this process ranges from 0.7 to 1.0 microns.

It can also be about 44 microinches.

The coating is dense, uniform, and flat giving an excellent soldering surface.

How is the PCB Immersion Tin Process done?

The process of applying this surface finish on your PCB consists of the following steps;

i. Pre-cleaning

This is the initial stage that you have to undertake.

You dip your PCB in an acid solution to wash away oil, grease, and other surface contaminants.

Also, you should do this to improve the effectiveness of the plating process.

You need to further rinse the surface with water to remove any remaining cleaning solution and surface debris.

ii. Micro-etching

In this process, you also dip the PCB in an acid solution preferably sulfuric acid.

The intent is to improve the copper layer structure by roughening it.

The intent of doing this is to prepare the copper surface to effectively bind with the tin layer.

Additionally, you should clean the surface with water to remove any residues of the etching compound.

iii. Pre-immersion

To prevent early oxidation of the copper surface that may alter the process, you immerse the board into an acid.

This also provides a good foundation for the tin material deposition.

iv. Immersion Tin

In this step, you dip the PCB in a solution containing tin cations to facilitate the electroless reduction process.

The copper metal is reduced by the tin ions present in the solution.

This consequently develops a consistent, flat, and thin tin layer on the copper pads.

Do this while closely monitoring the process and adhering to the right temperature alongside solution composition to achieve good results.

v. Post-cleaning

Here, you clean the plated PCB with water, which preferably should be warm.

You should do this to completely remove all plating salts and to prevent staining when drying.

When you poor rinsing, the board will end up appearing dull.

vi. Drying

After cleaning the boards, you need to dry them.

This will remove any sort of moisture content.

You can do this by either using clean forced air drying or by a warm oven bake.

You should operate the oven at the appropriate temperature.

Also, consider baking duration to preserve the PCB integrity.

How does Immersion Tin compare to Immersion Gold PCB Surface Finish?

These two PCB surface coating methods have various comparisons.

Some of which are;

  • Immersion tin is relatively cheaper than immersion gold.

This is due to the high cost of materials and long process in immersion gold plating.

  • The process steps for immersion gold are quite complex when you compare them with immersion tin which is simpler.
  • Immersion gold offers you a longer shelf life of 12 months.

This is contrary to immersion tin which lasts for not more than 6 months while under storage.

  • Immersion tin is not ideal for plated through holes on the board. On the contrary, immersion gold does well with this design feature.
  • Immersion gold offers you outstanding electrical performance when you compare it with immersion tin.
  • Immersion tin is easily reworkable in case you experience defects while surface mounting components.

On the other hand, immersion gold is difficult to rework thus you cannot repair.

  • Immersion gold is susceptible to experiencing black pad due to the use of phosphorus while immersion tin is not.
  • Immersion tin is likely to develop whiskers.

This is a phenomenon that is not existent when using immersion gold plating.

  • Both surface finishes are RoHS compliant making them environmentally friendly.

You can as well use them to assemble consumer electronics.

  • They also have excellent surface planarity that makes them ideal for soldering components.
  • Immersion gold is more oxidation resistant enabling it not to tarnish easily when you expose it to the environment.

On the other hand, immersion tin is prone to oxidation.

This jeopardizes its longevity causing it to demand stringent storage and handling requirements.

Venture Electronics offers a range of PCB surface finish options such as immersion silver PCB, ENIG PCB and OSP PCB, amongst others.

Depending on your specific needs, Venture Electronics will choose a PCB surface finish for your specific requirements.

Contact us now for the best prices on PCB fabrication.

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