OSP Technological process
Brife process as below:
Oil removal → secondary water washing → micro corrosion → secondary water washing → acid washing → deionized water washing → film formation → deionized water washing → drying
1,Oil removal: it directly affects the quality of film formation
2, microetching: The purpose is to form a rough copper surface that is easy to form a film. The general micro-corrosion thickness control in 1.0um to 1.5um is more appropriate, in order to measure the micro-corrosion rate before each production.
3, Film formation: Better to wash with deionized water before and after film formation, with PH value controlled between 4.0 and 7.0 to prevent contamination. The key to the OSP process is to control the thickness of the antioxidant film, which can easily affect the welding performance.
About OSP boards assembly
2.1 Incoming PCB should be vacuum packed with desiccant and humidity display card. For transportation and storage, please use insulating paper.
2.2 Do not expose to direct sunlight, maintain a good warehouse environment, relative humidity: 30 to 70%, temperature: 15 to 30°C, storage period of no more than 6 months.
2.3 When opening boxes at SMT site, do not open more than one box at a time, otherwise it will easily cause bad quality welding accidents.
2.4 Do not stay in the furnace after printing (stay should not exceed 1 hour), because the flux in the solder paste has a strong corrosive effect on the OSP film.
2.5 During the production process, avoid direct contact with the PCB surface by hand to avoid oxidation by sweat contamination.
2.6 After SMT, DIP hand inserts in the shortest possible time (up to 24 hours).Wet baked OSP PCB can not be used.
2.7 Useless expired empty boards, damp empty boards after a bad printing batch should be returned to the circuit board manufacturer for OSP rework and reuse, but the same board can not be used more than 3 times for OSP rework.
What need to attention when OSP pcb test?
With OSP surface treatment, if the test point is not covered by solder, it will cause contact problems with the needle bed fixture during ICT testing. There are many human factors that can affect the ICT test results.
Some of these factors are: OSP provider type, number of passes in the reflow oven, whether it is a wave process, nitrogen reflow or air reflow, and the type of simulation test in ICT.
Merely changing to a sharper probe type to penetrate the OSP layer will only cause damage and puncture the PCA test via or test pad. Therefore, it is strongly recommended not to directly probe the exposed copper pads, and it is required to consider tinning all test points when opening the steel mesh.
Venture OSP PCB is a water-based organic surface finish utilized in copper pads. They bond to copper and protect the copper pad before welding.
We are a professional OSP PCB manufacturer in China that offers environmentally friendly finish OSP PCB. Our OSP PCB is lead-free, provides a flat surface, and requires little maintenance. However, OSP PCB can be sensitive when handled.
This organic finish can keep copper from being oxide, thermal shock or moisture
Your Leading OSP PCB Supplier in China
Venture offers various types of surface finishes of your PCB such as OSP. OSP is short for “organic solderability preservatives”, and it’s also called anti-tarnish.
OSP PCB is referred to as an organic layer in terms of surface finishing of the board. They adhere to the copper by means of adsorption. Since Venture OSP PCB is organic, it is a permanent wall to prevent thermal shocks moisture and oxidation of copper.
Venture OSP PCB organic coating gives less deposition or easy removal of flux soldering. It helps reduce the soldering time of the assembly process of the printed circuit board.
Venture OSP PCB is the most popular surface finishing process across the printed circuit industry due to its easy processing and low cost.
Some advantages of Venture OSP PCB are:
- simple Manufacturing process
- gives a good performance in terms of solder wetting and joining between flux, vias, and pads
- water-based compound
- implemented a simple chemical compound and less complexity of the process
- implemented with single-side SMT assembly as well as double-sided SMT assembly
When it comes to surface finishing process for PCBs, our design engineers carefully followed on a certain principle required during transportation and storage of the OSP process:
- Vacuum packaging could be a solution
- OSP surface finished printed circuit boards are not directly exposed to sunlight
As a professional manufacturing company, Venture is an expert in manufacturing high-end OSP PCB. Venture OSP PCB supplier has a wide range of PCB products, ideal for your projects.
Venture provides quick-turn prototype PCBs compatible with standard PCBs and IPC1 with standard IPC2 with a short turn time. Excellent quality and competitive rates have been our business core for more than 10 years.
Up to the present, Venture wons a customer satisfaction rate as high as 99% from more than 10,000 customers around the globe.
Be one of Venture’s satisfied clients now!
OSP PCB – The Ultimate FAQ Guide
If you have any question about OSP PCB, your answer is right here.
From material type, manufacturing process, preferred finish, to application – you will find every information in this guide.
- What is OSP PCB?
- What are the Steps of Manufacturing OSP PCB?
- What are the Advantages of OSP PCB?
- What are the Disadvantages of OSP PCB?
- What are the OSP PCB Finish Problems?
- How can you Prevent OSP PCB Finish Problems?
- What are the Storage Requirements of OSP PCB?
- What Considerations should you Make when Selecting OSP Finish for PCB?
- What Materials are used in OSP PCB Finish?
- Is OSP PCB Baking Recommended?
- How long can OSP PCB Last before use?
- What is the Difference Between OSP and HASL Finish in PCB?
- What is the Thickness of OSP in PCB?
- Why is OSP Finish Preferred?
- What Type of Chemical Compound is used in OSP PCBs?
- Why is Micro Etching Important in OSP Finish Process?
- What Causes Tarnishing in OSP PCBs?
- Why do OSP Finish require Special Handling?
- What is the Comparison of OSP and ENIG PCB Finish?
What is OSP PCB?
Organic Solderability Preservatives (OSP) is a technique of surface protection of a Print Circuit Board (PCB).
It comprises of an organic surface finish generated on exposed copper by adsorption.
This organic surface is able of stop thermal shock, oxidation of copper as well as copper exposure to moisture.
The water-based compound is of the azole group which may include imidazoles, benzotriazoles among others which will be adsorbed on the surface of copper.
The adsorption leads to generation of films.
While it protects copper, it has to be easily removable through Flux while soldering.
This enables easy jointing if clean copper with melting solder through allowing generation of solder joints in a very short duration.
What are the Steps of Manufacturing OSP PCB?
The first step in OSP PCB manufacturing is cleaning which involves removal of contaminants including oil, fingerprints or oxidation remains.
This step is important in ensuring that the preservative build is of the same thickness all over the copper surface.
The second step involves the formation of a slightly rudimentary surface on copper which will allow easy generation of film.
This topographic modification may in some instances remove oxidation generated on copper which might hinder OSP solution attachment to copper.
This is followed by deionization (DI) washing to remove other ions which might have contaminated the copper surface.
Film formation is then carried out; DI rinse is repeated to remove possible ion contamination after preservative build with a PH value of between 0.4 and 7.0.
What are the Advantages of OSP PCB?
OSP coated Print Circuit Board perform well during soldering.
OSP coated boards are very flexible and can be easily repaired when damaged.
PCB manufacturers can rework the circuit boards with no trouble so that assemblers can generate new coating when needed.
OSP is environmental friendly because it uses a water-based complex to generate the coating on copper which is not a threat to the surrounding.
OSP is the best selection for electronics which meet the environmental standards set.
The simple development process and application of simple elements reduces the cost of manufacturing and fabrication of PCB.
OSP PCB can be stored for a long duration; with the correct storage condition, OSP coated boards can be stored for long.
These conditions include vacuum storage and relative humidity.
What are the Disadvantages of OSP PCB?
OSP coated boards are very thin and are always predisposed to scratches.
This creates difficulties during transportation since they can be damaged.
OSP films generated are prone to color change or cracks on the surface.
Cracks might affect reliability on using electronics with this board design.
There is no possible way of measuring the thickness of OSP during generation.
Thickness must be controlled to a given level and without a clear framework it becomes a problem.
OSP coated boards require sensitive handling since they are prone to cracks and scratches.
OSP finished boards have a short shelf life of approximately one year after which it starts degrading and the copper underneath is oxidized.
OSP finished boards are not suitable for Plated Through Holes (PTH) and can lead to ICT issues.
What are the OSP PCB Finish Problems?
OSP finished boards may change color after soldering.
Color might change from brown to dark brown this is an indication that the OSP coat has been compromised.
Tarnish may also occur which may be as a result air exposure for a long duration after manufacture and packaging by the supplier.
OSP boards might develop oxidation spots which might be due to improper application on the surface.
Oxidation signs should be dealt with before application of the coating.
Micro etching is done significantly to remove oxidation developed on copper, oxidation after coating indicates improper application.
OSP finished boards may also start forming darker color or a uniform color.
This darker color or uniform color might occur due to exposure to high relative humidity and temperature.
How can you Prevent OSP PCB Finish Problems?
OSP finish problems are prevented through flux in the process of soldering.
This removes oxidations so that soldering ability won’t be impacted.
The thickness of the OSP coating should be regulated within a given level for proper and effective coating preventing finish problems.
The quantity of micro-etching should be regulated within a given range to extensively remove oxidation on copper before coating.
Oxide developed on copper should be removed through micro-etching through a regulated speed which impacts film build rate.
Another way of preventing OSP finish problems is proper OSP application with regulated thickness.
Proper storage at relative humidity and temperature and noting of shelf life duration that is before twelve months.
Deionization should be done before and after coating this removes ion contaminants which might be present.
What are the Storage Requirements of OSP PCB?
OSP Copper PCB
Preservatives developed by OSP technique are so tiny and can be damaged easily this requires sensitive handling, transportation and storage.
Exposure of OSP coated boards to high temperatures and humidity leads to oxide development on PCB.
Storage of OSP PCB should observe the following; utilization of vacuum packaging with a desiccant and humidity indication card.
This creates a relatively humid and optimum temperature for storage.
During packaging of OSP coated PCB it is advised to put release paper between them to prevent friction which might damage the PCB surface.
OSP finished PCB should not be exposed to direct sunlight, direct sunlight damages the OSP coating due to high temperatures and high atmospheric humidity.
The storage span should be less than twelve months because of short life span.
What Considerations should you Make when Selecting OSP Finish for PCB?
Choosing OSP finish will rely on several aspects, including the finishing procedure, the PCB’s plan and the value of the last outcome.
Some of the aspects to consider include:
Solderability where one needs to avoid soldering problems to come up with a PCB that will function as required.
Reflect on whether the finish can solder perfectly to the copper which makes OSP a suitable finish for this case.
Processing duration, for a particular finish may be long or short.
Finishes such as HASL have bigger processing duration and this ought to be considered when choosing OSP finish.
Reliability which entails the measure of how well the selected surface finish can withstand its setting should be considered.
Corrosion where the vulnerability of the material to corrosion should be considered when choosing OSP finish.
Some surface finishing kinds such as silver are susceptible to oxidization compared to others.
What Materials are used in OSP PCB Finish?
Surface finishes are made from a variety of materials.
These materials include:
· Electroless Nickel Immersion Gold (ENIG)
ENIG finishes comprise of two coats prepared from metal cover.
The covering is a coating of gold that shields a coat of nickel.
The gold shields the nickel whereas it is in store by offering a minimal connection resistance.
· Hard Electrolytic Gold
Similar to ENIG, this finish material is prepared from a coat of nickel sheltered by a coat of gold.
The coat is tough gold, to shield the nickel in extreme-wear settings.
· Organic Solderability Preservative (OSP)
This material is ordinarily prepared from organic stabilizers that inhibit the copper plate of a PCB from oxidizing.
A tinny coat of OSP is positioned right above the PCB to shield it before soldering it to an additional device.
Immersion silver finish materials are mutually metallic and organic.
The materials are prepared of silver and OSP coats.
The OSP protects the silver from changing, which prolongs its shelf duration nearly 12 months.
Immersion silver PCB
Is OSP PCB Baking Recommended?
Baking boards with an organic solderability preserve (OSP) surface finish may lead to some undesired outcomes.
Even though the results may not be desirable, the procedure can have helpful performance in specific applications.
Baking a board with organic solderability preserve re-exposes the copper plate.
OSP is extremely susceptible to oxidation and can be effortlessly detached from the padding.
Baking settings and extra usage are harmful to OSP PCB finishes.
When there is need for baking, it is suggested that just a minor piece be open to a bake phase initially.
When the bake phase is completed there is need to test for solderability.
Simply bake what will be gathered instantly because baking settings will result to the OSP circuit board oxidizing more rapidly during storage.
How long can OSP PCB Last before use?
OSP PCB produces a preservative that is very tinny and can be easily cut.
As such, a lot of caution must be taken in the procedure of operating and transporting the preservative.
OSP PCB surfaces are exposed to extreme heat and moisture for a prolonged duration.
Due to this corrosion will be probably produced on the surfaces of PCB which leads to minimal solderability.
To curb this corrosion, storage procedures ought to follow certain set standards.
Vacuum packages ought to be used with desiccant and moisture displaying card.
Place release broadsheet in between PCBs to curb friction which destroys the surfaces. Additionally, OSP PCB cannot be openly exposed to the sun rays.
The standards for optimum storing setting comprise relative moisture of about 30-70%, heat levels ranging from 15-30°C and storing period less than 12 months.
What is the Difference Between OSP and HASL Finish in PCB?
Organic Solderability Preservative comprises a water-based organic surface finish that is usually utilized for copper padding.
The preservative selectively attaches to copper and guards the copper padding afore soldering.
OSP is ecological friendly, offers a coplanar surface, is lead-free and needs minimal tools upkeep.
Nevertheless, it is not as strong as HASL and can be delicate therefore it needs to be handled carefully.
Over the years, HASL was amongst the most widely used surface finish selections.
Recently, companies have recognized its restrictions.
Mostly,PCB surface finish may be cheap and strong.
However, important modifications in the PCB manufacturing including the emergence of multifaceted surface mount skills have uncovered its deficiencies.
HASL leads to rough surfaces and is not appropriate for good pitch elements.
Even though it is designed to be lead-free, it is not as reliable when compared to OSP.
Types of PCB surface finish
What is the Thickness of OSP in PCB?
Mostly, OSP is a clear shielding film which cannot be easily noticed through a simple glance.
Additionally, there is no huge variation between the naked cooper plate and OSP surface completed sheet.
This makes it hard for the sheet industrial unit to recognize and determine the value.
In case the OSP shield unluckily has an opening on the copper plate, the copper film will begin corrosion from the open part.
Then, become an additional undesired aspect to affect SMT mounting.
For that reason, the OSP has to be thicker to ensure the better safeguarding for copper film.
Putting into consideration the necessity to be unpolluted by fluidity and dilute acid, so the usual thickness of OSP is 0.2 – 0.65um and has a shelf duration of 6 months.
Why is OSP Finish Preferred?
The main reason why most people prefer OSP finished boards is its affordability.
OSP boards are less expensive compared to those invented by use of surfaces including HASL, Immersion Silver and ENIG.
OSP finish is also preferred due to the evenness of the pads.
The key shortcomings are associated with solderability, shelf life, re-using misprinted boards and numerous heating phases.
In the event that OSP is damaged within a period of less than a year, the Copper beneath corrodes quite simply and inhibits the board from easy to soldering.
Re-using misprinted boards is also a problem since solvents applied to clean misprinted boards also eliminate the OSP leading to oxidization.
Lastly, modern OSP materials are highly preferred due to the fact that they can overcome susceptibility to solderability hitches when exposed to numerous heating phases.
What Type of Chemical Compound is used in OSP PCBs?
OSP is an extremely tinny organic undercoat on the PCB board.
It comprises of a water-based chemical element of the Azole family including benzotriazoles, imidazoles, as well as benzimidazoles.
This element is then absorbed by the uncovered copper and produces a shielded coat.
OSP is an ecological friendly element when compared to other lead-free PCB finishes.
OSP is a better lead-free finish, with extremely even surfaces for SMT Assembly, although it has a comparatively brief shelf life.
When applying this surface polish, the PCB is immersed into a chemical solution of the OSP element.
However, this is done after every other PCB construction procedure is completed.
It comprises of Electrical Testing, Visual Examination and Automated Optical Inspection (AOI).
Why is Micro Etching Important in OSP Finish Process?
During topography improvement, micro etching is normally conducted to considerably eradicate the oxidation on copper foil.
Micro-etching ensures that the connection forces can be enhanced between copper coating and OSP compound.
The quickness of micro etching affects the coat generation speed.
So as to get even and uniform coat thickness, it is important to maintain the steadiness of micro etching quickness.
It is appropriate to regulate the micro etching speed within the level of 1.0 to 1.5μm per minute.
It is appropriate to ensure that deionization solution is used before stabilizers form in case OSP component will be contaminated by other ions.
The contamination may result to discolor after reflow soldering.
Correspondingly, it is suitable that deionization solution should be used after stabilizers form with the PH value of 4.0 to 7.0.
That is, in case stabilizers are destroyed due to contamination.
What Causes Tarnishing in OSP PCBs?
In some instances, the color of OSP boards appears different after soldering.
This in most cases is associated with stabilizers being thick, micro etching amount, soldering intervals and also irregular pollutants.
Fortunately, this problem can be detected just as it starts to appear.
Ordinarily there are two situations and for the first situation in the course of soldering, fluidity is able to assist in eradicating oxidations.
This ensures that soldering function will not be affected.
For that reason, no more dimensions have to be obtained.
On the other hand, the other situation happens due to OSP reliability being damaged so that fluidity is not able to eliminate oxidations.
This damage most definitely results in decreased soldering functioning.
Why do OSP Finish require Special Handling?
OSP is intended to create a tinny, even, shielding coat on the copper plate of the PCB’s.
This coat shields the circuit from oxidization in the course of storing and assembling processes.
PCB builders have found a simple way of controlling oxidization.
PCB assembly, it has got greater abilities over outdated HASL in terms of solderability.
Cautious usage is required as acidic thumb print damage the OSP and make the copper vulnerable to oxidization.
Manufacturers choose to use metallic finishes that are highly elastic and withstand high temperature phases.
Oxidization can also cause main hitches at ICT with the nails fitting connection.
Forceful probing is necessary to get into the OSP coating which can cause destruction and penetrating of the PCB examination through or assessment ideas.
What is the Comparison of OSP and ENIG PCB Finish?
OSP is comprised of a water-based, organic finish that is normally utilized for copper padding.
It works by bonding to copper and protecting the copper padding afore soldering.
OSP is not as strong as ENIG and can be sensitive while handling.
Conversely, ENIG comprises of a dual layer metal coat, with nickel performing as mutually a barricade to the copper and a plate to which elements are soldered.
A golden coat shields the nickel in the course of storing.
ENIG is the solution to main business developments including lead-free needs and emergence of multifaceted surface elements which need even surfaces.
However, ENIG can be costly, and can sometimes lead to black pad condition.
This is an accumulation of phosphorous in the middle of the gold and nickel layers.
This accumulation leads to fracture in surfaces and defective networks.
Now, we would like to hear from you.
You can contact Venture Electronics team in case you have any questions or inquiries on OSP PCB.