Copper Clad Laminate (abbreviated CCL) is a base material for PCBs. A copper-clad panel is made by laminating glass fiber or wood paper with copper on one or both sides after the material has been soaked in resin.

2. How are CCLs classified?

CCLs are classified according to different standards.

1. We have rigid CCL (FR-4 CEM-1, etc.) based on the mechanical rigidity of CCL. Flex CCL. Flex PCBs rely on flex and rigid CCLs.
2. We have organic resin CCL in FR-4 (FR-4), CEM-3 (CEM-3), etc., metal-base CCL, ceramic-base CCL, etc.
3. We have two types of CCL based on thickness. The thickness of the former must be at least 0.5mm, while that of the latter may be less than 0.5mm. The CCL thickness does not account for copper foil thickness.
4. We have glass fiber cloth CCL, paper CCL, and compound CCL.
5. We have two types of CCL based on the insulation resin used: Phenolic (FR-1,XPC) and epoxy CCL.

3. What makes a good CCL?

CCLs can only meet performance requirements when they are able to cater to the following:

1. Appearance. Unexpected elements in the production process, like dents or scratches, resin points, wrinkles, pinholes, bubbles, etc., might have an impact on copper foil. These issues will all result in a poor CCL and, eventually, a PCB.A CCL that is excellent should have a flat, smooth appearance.
2. Size. As CCLs are the base material for PCBboards, they must conform to the size requirements of PCBs. The size of CCLs is determined by several parameters, including length, width, and diagonal deviation.
3. Electrical performance. It is essential that a PCB achieves this mission. Therefore, any factor affecting the electric performance of the board must be designed carefully. This includes dielectric constant, dielectric loss tangent, volume resistance, surface resistivity, insulation resistance, and arc resistance.
4. Performance. The physical performance of CCLs is determined by dimensional stability (PS), peel strength (PS), bend strength, heat resistance, thermal stress (Td, T260, T288, and T300), punching qualities, etc.
5. Chemical Performance. The chemical performance of CCLs must meet requirements such as flammability and chemical resistance to reagents, Tg, Z axis coefficient thermal expansion (Z CTE), dimensional stabilities, etc.
6. Environmental performance. It must meet the requirements of water absorption, etc.

PCB Fab Houses should perform CCL quality judgment. AssemblePCB, for instance, uses IPC-4101C for manufacturing standards and IPC-TM-655 for CCL tests. CCLs are therefore qualified as PCB substrates when they meet these standards.

4. Prepreg: What is it?

Prepreg is the reinforcing material found within a CCL. It is baked and composed of glass fiber. Some people call it a bonding sheet, and it is composed of epoxy resin, DMF cloth, 2MI, Acetone, etc.

Classification of prepreg. There are many classification standards for prepreg.

1). Based on glass fibre cloth: 106; 1080; 2112; 2116. 1500 and 7628.

2). Based on the resin used and its performance, POLYCLAD Turbo254/226, ISOLAFR402/FR406,ITEQIT180, Sheng YiS1141-140/170

Resin Classification

1)Phenolic resin

2)Epoxy resin

3)Polyimide resin

4) Polytetrafluorethelene resin (PTFE or TEFLON resin)

5) Bismaleimide triazine (BT)

Glass Fiber is characterized by the following attributes:

1)High intensity

2) Fire and heat resistance

3) Humidity Resistance

4) Excellent insulation capabilities

Factors that affect the quality of prepreg. A high-quality prepreg will lead to a high-quality PCB, and then CCLs. AssemblePCB is very concerned with the quality of prepreg, and tests and controls it in terms of resin, gel time, and resin fluidity.

Select prereg according to cost. Glass fiber cloth is the main factor in the high cost of prepreg. In general, prepreg costs are directly correlated with the thickness and quality of the glass fiber cloth. The cost of prepreg increases as the thickness of the cloth decreases. Prepreg 1080 is cheaper than prepreg 1112 because it is rarely used.

5. What Is Copper Foil?

The following table summarizes copper foil by technology and class.

Copper foil is classified according to its performance. Standard copper foil is used for FR-4 or paper base boards, HTE is used for multilayer PCBs in order to feed back the split ring issue, and low profile copper foil is also applied to multilayer PCBs.

6. A New Trend in CCL

To meet the RoHS regulations (restriction of hazardous substances), CCLs are subjected to higher standards in terms of reliability and heat resistance. The following two aspects are modified:

Halogen-free CCL. This refers to CCLs with a chlorine (Cl), bromine (Br), and overall content that is not more than 1500ppm. The following table summarizes the performance comparison between ordinary FR-4 and halogen-free FR-4 CCLs.

Lead-free CCL. This type of copper-clad PCB does not use lead-free solder for surface mounting. Brominated epoxy resin is the primary resin used in lead-free CCLs. The RoHS states that six chemicals, including PBDE and PBB, are no longer utilized in CCLs. Ordinary FR-4 CCLs adopt the DICY curing system (with dicyandiamide as the curing agent), while lead-free CCLs adopt the PN curing system (with phenol-formaldehyde resin as the curing agent).

The PCB and CCL industry has accepted standards for peel strength of halogen-free CCLs as well as lead-free CCLs.

Backed by over 12 years of dedicated efforts and industry experience, AssemblePCB has been making active contributions to the growth and prosperity of the PCB sector. It is well-prepared to deliver high-quality, eco-friendly PCBs—along with the corresponding types of copper clad laminates (CCLs)—at competitive price points.

AssemblePCB, one of the top PCB manufacturers in the world, offers excellent, environmentally friendly PCBs. Join together with AssemblePCB for top-notch PCB solutions. Get a free quote right now!

OrinewPCB has been providing reliable one-stop PCB solutions for over 14 years, covering everything from PCB manufacturing and electronic component sourcing to assembly, testing, and IC programming. With a strong commitment to quality and fast delivery, we help global clients bring their products to market efficiently.

The post A Detailed Overview of Copper Clad Laminate first appeared on Assemblepcb.

1. Understanding SMD Components

Electronic parts that are physically affixed to printed circuit boards (PCBs) are known as surface-mount devices. Through-hole technology components (THT), which require that holes be drilled into the PCB to install, have been largely replaced by SMD components. SMD components enable a more efficient and compact design because of their reduced size.

SMD components are essential to the operation of electronic devices. These components are found in almost all electronic devices, such as computers, mobiles, and household appliances. They are primarily used to control the flow in an electrical circuit. However, depending on their specific type, they can perform other tasks.

SMD components offer several advantages compared to traditional through-hole parts. They are lighter and smaller, allowing for smaller electronic devices. They can also be placed on the back and front of a PCB to increase circuit density. This allows for more complex designs. SMD components are installed by automated equipment which lowers production costs and speeds up production.

2. Basic Types SMD Components

Surface Mount Devices (SMDs) are available in many types. Each type has a unique function within an electronic circuit. SMD components are mainly resistors and capacitors.

2.1 Resistors

One of the most popular types of SMD components is resistors. They limit the flow of electric current in a system. Resistance is measured by ohms. SMD resistors have resistance values that range from 1 ohm up to several megaohms.

SMD resistors are available in different types. Every kind is made for a certain need. Thin-film resistors, for example, are renowned for their precision and stability. For precision applications like instrumentation, they are therefore perfect. The resistance values range from 1 ohm up to 3 megaohms with tolerances as low as 0.1%.

However, compared to thin-film resistors, thick-film resistors are less widely used and less expensive. They are employed in general-purpose settings where accuracy is not necessary. Thick-film resistances come in a range of values from 1 ohm up to several gigaohms. Tolerance values are typically between 1% and 5%.

A current sense resistor is another type of SMD resistance that is used to measure electrical current. These resistors are very low resistance, usually less than 1ohm. They produce voltage drops proportional to current flow. After that, the voltage drop is monitored and utilized to determine the current.

Metal foil resistors and wire-wound resistors are also available in high precision and high stability. The application’s requirements determine the type of resistor that is selected.

2.2 Capacitors

Another fundamental SMD component is the capacitor. Like a temporary battery, they store and release energy. Among the many uses for capacitors are energy storage, voltage stabilization, and noise reduction.

Farads are used to express capacitance, which is a measurement of the capacitor’s capacity to hold charge. Most capacitors in electronic circuits, however, have capacitance values that fall in the range of microfarads (μF), Nanofarads (nF), or Picofarads (pF).

There are numerous varieties of SMD capacitors, each having special qualities of its own. The most common SMD capacitor type is ceramic capacitors. These capacitors are cheap, offer a range of capacitances, and can be mounted in either direction. Their capacitance may vary depending on temperature and voltage. This can be a disadvantage for precision applications.

Tantalum capacitors are another type of SMD. These capacitors are more expensive, but offer better stability and higher capacitance than ceramics. Tantalum capacitors’ high capacitance-to-volume ratio makes them common in power supply circuits.

SMDs can also be film capacitors. High levels of accuracy, stability, and dependability are possessed by film capacitors. High-frequency applications like RF circuitry and high-quality audio employ them.

The final kind of capacitor is an electrolytic capacitor. They have a higher capacitance but less stability and accuracy. These capacitors are polarized, and their lifespan is limited when they’re used at high temperatures. Circuits that need a lot of capacitance can use electrolytic capacitors.

The choice of a capacitor depends on the application. Each type has strengths and weaknesses.

2.3 Inductors

Another kind of SMD component that is crucial to electronic circuits is the inductor. They are used to store power in magnetic fields when electric current flows through them. Inductors are used primarily in analog circuits to stabilize current flow and filter out high frequency noise.

During the PCB manufacture of an electronic device, a toroidal inductor and transformer are used.

Inductance is measured in henries. Inductors in electronic circuits typically have values of inductance in the range of microhenries (μH) and nanohenries (nH).

The most prevalent kind of SMD inductor is a wirewound inductor. The most common SMD inductor is the wirewound type. These inductors are wound around a core of magnetic material and offer high inductances. Their inductance can change with frequency, and this is a disadvantage for high-frequency applications.

Multilayer inductors are another type of SMD. Multilayer inductors offer high inductance in a small package. Multiple layers of magnetic material are stacked to create them. They have a lower capacity to handle current compared with wire-wound inductors.

Ferrite-bead inductors are used in electronic circuits to cut down on high-frequency noise. The inductors are created by threading wires through bead material made from ferrite. Ferrite-bead inductors are very resistant to high frequencies. This allows them to filter out high-frequency noise.

The choice of an inductor depends on the requirements of the application. A wire-wound coil inductor, for example, might be selected for a circuit of a power supply due to its ability to handle high currents. A ferrite-bead inductor, on the other hand, might be selected for a circuit of signal processing due to its noise filtering capabilities.

3. Advanced SMD Component Types

Advanced SMD component types include integrated circuits, diodes, and transistors. These components are more complicated than surface mount components. They are employed in many different applications, such as ICs, signal processing, and power control.

3.1 Diodes

Semiconductor devices called diodes permit one direction of current flow while obstructing the other. They can be used for a variety of applications such as voltage regulation, signal processing, rectification, and more.

SMD diodes are available in a variety of types. Each type has its own unique features and applications. In power supply, a popular form of rectifier diode is used to convert AC to DC. Rectifier diodes can handle high currents and withstand reverse voltages.

SMD diodes come in a number of varieties. Their rapid switching rates and low forward voltage drop are well-known. High-frequency applications, including radio frequency (RF) circuits and power supply switching, employ Schottky diodes.

The Zener diode is another kind of SMD. It is employed to control voltage. Beyond a certain voltage, they start to conduct in reverse. They can maintain a constant current across their terminals. They are therefore perfect for voltage-regulating electrical circuits.

LEDs are a type of diode that emits light whenever a current is passed through them. Display panels and indicator lights are only two of the many uses for SMD LEDs.

A triode is a type of electronic vacuum tube that has three electrodes: a plate, a grid, and a filament (cathode). Compared to through-hole triodes, SMD triodes have a number of benefits and are used in many electrical devices.

The choice of a diode depends on the requirements of the application. For instance, a Schottky may be used for high-frequency applications because of its fast switching speed, whereas a rectifier diode may be chosen for a power supply because of its capacity to manage high currents.

3.2 Transistors

Electrical signals can be switched or amplified using semiconductors known as transistors. Transistors are a key component in the current electronics industry. They are used in a wide range of applications, including digital logic and power amplifiers.

There are numerous varieties of SMD transistors. Every variety has special qualities and uses of its own. The bipolar junction transistor is a common type. It can be either PNP or NPN and has two connectors. Applications for BJTs are numerous and include switching and amplification.

Another SMD type is the field-effect transistor. It controls the flow of electricity via a semiconductor. The two main subtypes of FETs are metal-oxide-semiconductor field-effect transistors (MOSFETs) and junction gate field-effect transistors (JFETs). Applications needing low noise and high input impedance usually use JFETs. In contrast, MOSFETs are frequently employed in high-speed switching applications.

MOSFETs have become very popular in electronics because of their fast switching speeds, low power consumption, and high input resistance. MOSFETs come in two varieties: enhancement-mode and depletion-mode. Depletion-mode MOSFETs and enhancement-mode MOSFETs require gate voltages to be turned on.

The choice of a transistor depends on the requirements of your application. A BJT may be selected for a linear amplifying circuit because of its high current gain. However, a MOSFET could be selected for a switching supply due to the high switching speed and lower power consumption.

3.3 Integrated Circuits

Electronic components comprising several parts on a single chip, such as resistors, diodes, and transistors, are called integrated circuits. There are numerous uses for ICs. They are found in microprocessors, memory chips, analog-to-digital converters, and power management circuits.

SMD ICs are available in a variety of types, with each type being designed for a particular application. digital IC is a common type, which includes microprocessors and microcontrollers as well as digital signal processors. Digital ICs can be found in many applications that require the processing and manipulation of digital data. Computers, smartphones, and digital audio equipment are a few examples.

Another kind of SMD IC is analog, which includes operational amplifiers, comparators, and voltage regulators. Applications like audio amplifiers, sensors, and power supply that need to process analog signals can make use of analog integrated circuits (ICs). Analog and digital circuitry are combined onto a single chip in mixed-signal IC integrated circuits. These ICs are used for applications that require digital and analog processing, such as radio frequency (RF), data converters, and other circuits.

Power Management ICs are a subset of SMD ICs that are used in electrical devices to distribute and control power. Voltage regulators, battery chargers, and power switches are all part of this group. Applications for power management integrated circuits (ICs) are numerous and include solar power systems, electric cars, computers, and cell phones.

The application’s requirements determine which IC is best. Every type of IC has advantages and disadvantages of its own. A digital IC, for example, might be selected for a motherboard of a computer due to its high-speed processing capabilities. An analog IC, on the other hand, might be selected for an audio amplifier due to its ability to process analog signals.

4. Sizes of SMD components and codes

The size and code of SMD components are important to know when choosing and using them in electronic circuits. SMD components are classified by their size and code, which provides information on the physical dimensions and electrical properties. This enables technicians and engineers to choose the appropriate part for particular uses.

Standard code systems consisting of alphanumeric letters are used to identify SMD components. The code system used varies according to the component type, like resistors or capacitors.

4.1 Resistor sizes and codes

The code of SMD resistors is a three- or four-digit number that indicates the resistance value and the tolerance. The resistance value is represented by the first two or four digits, and the multiplier is indicated by the last digit. A resistor coded “103” would have a resistance of 10 x 10^3 Ohms or 10 Kilohms.

The standard size of SMD resistors is also denoted with a two-digit number, for example, 0402, 0805, 0603 or 0805. The first two numbers represent the resistance’s length in hundredths, and the last two represent its width. A 0603 resistor, for example, measures 0.06 inches long and 0.03 inches wide.

4.2 Capacitor sizes and codes

The three-digit code identifies SMD capacitors and indicates the capacitance rating as well as the voltage rating. The multiplier is the final digit, while the capacitance’s significant values are the first two. A capacitor coded “104” would have a capacitance of 10 x 10^4 picofarads or 100 nanofarads.

SMD capacitors are also available in standard sizes such as 0603 or 0805. The size code is the same as for resistors. The width is represented by the final two digits, whereas the length is represented by the first two.

4.3 Inductor sizes and codes

Inductors SMD are identified by four-digit codes that indicate their inductance and tolerance. The multiplier is the final digit, while the first three represent the inductance’s significant figures. The inductance of inductor code 1002 is 10 x 10^2 Microhenries, or 1 Millihenry.

Inductors are also available in a variety of standard sizes. They look similar to capacitors and resistors. The size code is the same, with the width denoted by the last two integers and the length by the first two.

Understanding the surface mount component codes and sizes is essential for choosing the right components for specific applications and ensuring that electronic circuits work properly.

5. Selection and application of SMD components

It is important to select the right SMD package for an application in order to achieve the best performance and functionality of the electronic circuit. There are a number of things to take into account while selecting SMD components

5.1 Electrical characteristics

An SMD component’s electrical properties, such as its capacitance or inductance, must be suitable for the purpose for which it is designed. A resistor with the right resistance value, for example, is needed to limit current flow in a system. A capacitor with the correct capacitance is needed for energy storage or filtering. To determine the electrical characteristics required for a particular application, it is important to consult datasheets or reference designs.

5.2 Physical Dimensions

The dimensions of SMD components must match the available area on the PCB. The component size must also be compatible with the manufacturing process. Smaller components may need more precise placement or soldering techniques. Standard SMD component dimensions, such as 0603 or 0805, can be used to select components for specific applications.

5.3 Compatible with other components

Electrically and mechanically, SMD components need to be compatible with the other components of the circuit. When linked to a high-voltage source, a capacitor with a higher voltage rating is necessary. Similarly, a resistor of a higher power rating is needed if the component is being used in an application that requires a lot of current. To guarantee consistent performance throughout a broad temperature range, temperature-sensitive applications should also select components with comparable temperature coefficients.

5.4 Examples of SMD Component Selection and Application

1. A combination of SMD transistors, resistors, and capacitors can be used to filter and regulate the output voltage in a power supply. Input voltage, output power, load current, and efficiency requirements are taken into consideration when choosing these parts.
2. SMD inductors and capacitors can be used to create filters for radio frequency circuits that block certain frequencies while allowing others through. These components are selected based on desired filter characteristics such as center frequency, bandwidth and attenuation.
3. SMD resistors and capacitors can be utilized in timing circuits, decoupling capacitors, and pull-up or pull-down resistors in microcontroller-based circuits. These components are selected based on various factors, including the microcontroller’s input and output requirements.

The electrical characteristics, physical dimensions, and compatibility of other components are important factors in selecting the right SMT component for a particular application. This will guarantee the electronic system operates at its peak efficiency.

6. Soldering SMD Components

To ensure that electronic circuits work properly, it is important to use specific techniques and take precautions when handling and soldering SMD components. Surface mount technology (SMT), a process that uses surface mount technology to attach SMD connectors to PCBs, is usually used. Because SMD components are small and sensitive, they are more likely to be damaged.

6.1 Soldering Techniques

Solder paste is used to solder SMD components. It’s a mixture that contains flux and solder particles. Solder paste is applied using a stencil, syringe or pick-and place machines. The SMD components are placed onto the pads with tweezers. The solder paste is melted by heating the PCB in reflow furnaces. As a result, the component on the PCB forms a solid mechanical and electrical link. Ball Grid Array components (BGAs) are more difficult to solder or desolder as they are on the back of the package.

When soldering SMD parts, there are several important factors to take into consideration:

1. Quality of solder paste: Solder paste must have the correct viscosity, metal content, and consistency to adhere to PCB pads.
2. Stencil Design: A stencil must be designed so that the solder substrate is evenly distributed on each pad. This will ensure a good connection, without solder bridges and insufficient solder joints.
3. Reflow Profile: Program the reflow oven with an appropriate temperature profile that includes preheating and soaking stages, as well as reflowing, cooling, and reflowing. The solder paste will melt and form a strong joint without damaging either the PCB or the component.
4. Alignment of components: SMD components must be placed accurately on the PCB pads in order to ensure electrical and proper alignment.

QFP packages can be used to package high pin count SMD integrated components, such as memory chips, microprocessors, and field-programmable gates arrays.

6.2 Handling precautions

To avoid damage and to ensure the reliability and safety of the electronic circuit, it is important to handle SMD components with care. The following should be taken into account when handling SMD packages :

1. Electrostatic Discharge (ESD) Protection : Transistors and integrated circuits (ICs) are among the many SMD components that are vulnerable to electrostatic discharge. This may cause irreversible harm. It’s crucial to employ ESD-safe instruments like tweezers, workstations, and wrist straps when working with SMD components.
2. Stress from Mechanical Excessive mechanical forces, including twisting or bending, might harm SMD components. When handling and placing SMD components, It’s important to avoid using too much force.
3. Temperature controlSMD components are sensitive to humidity and temperature, and this can impact their electrical characteristics. It is crucial to handle and store SMD components in a regulated environment to guarantee long-term functioning.

It is possible to integrate SMD or SMT electronic components into circuits by using the correct soldering technique and handling precautions. This will ensure optimal performance and reliability.

7. Summary

Anyone involved in electronics must understand the different types of SMD components, their functions, and applications. Every component is essential to the functioning of electronic circuits, ranging from SOT components like resistors and capacitors to sophisticated components like integrated circuits, transistors, and diodes. For electronics to operate at their peak efficiency and dependability, these components must be carefully chosen, handled, and soldered.

8.FAQS

Q: What are SMD components?

A: SMD, or Surface Mount Device, components are electronic components designed to be directly mounted onto the surface of a printed circuit board (PCB), rather than being inserted through holes as with traditional through-hole components.

Q: What is the difference between SMT and SMD?

A: SMT is the overall process of mounting and soldering electronic components directly onto the surface of a printed circuit board (PCB). SMD refers to the components themselves that are designed for this surface mounting process.

Q: What temperature is needed to remove SMD components?

A: 350 to 380 degrees centigrade

Q: How do I identify SMD components?

A: Utilize reference charts, datasheets, and online resources to help identify distinctive codes, dimensions, and polarity markings.

The post A Complete Guide to SMD Components first appeared on Assemblepcb.

The various types of PCB surface finish will be covered in great detail in this blog. Additionally, you will learn how to choose the best finish for your particular PCB requirements.

1.The Definition of Surface Finishing on PCBs

Learn a bit about the surface finishes of PCBs.

In essence, a PCB surface finish is a protective layer applied to the copper trace of PCBs. It can increase PCB reliability and longevity. Surface finish promotes solder joints that are strong, which allows for reliable soldering.

Each type of finish is unique. This makes PCBs more suitable for specific applications. Most surface finishes work well with fine-pitch parts. These finishes can also prevent problems like solder mask shifting or tombstoning.

different pcb surface finish

2.There are different types of PCB surface finishes.

Understanding the importance of surface finish on your PCB. The best option for your project can then be selected. Each has unique benefits and drawbacks.

The various surface finish types will now be covered in detail.

2.1 Hot Air Solder Level (HASL)

The most widely used and reasonably priced surface finish is HASL. The procedure is fairly easy. Dip the PCB into the metal that has melted. The copper is then soldered to be removed from the tank. The PCB surface is leveled using hot-air knives. The surface is now solderable.

HASL can be used with both large components and SMTs. SMTs that are too small will not perform as they should. Fine Pitch Technology and Fine Pitch Technology are not compatible. Process temperatures can range between 260 and 270 degrees. High temperatures can damage circuit boards. This alloy contains a high amount of lead. Lead in the alloy is carcinogenic. It’s usually dipped into tin-lead. This means it’s not RoHS compliant.

2 .2 Lead-Free HASL

Lead-free HASL has the same properties as conventional HASL, but does not contain any lead. There are numerous applications for it. It is RoHS-compliant. It has all the advantages of traditional HASL.

2.3 Organic Soderability Preservatives(OSP)

OSP is the process used to finish printed boards with copper foil. It meets the RoHS directive. OSP stands for organic solvents preservatives.

OSP is resistant to heat shock, moisture, and oxidation. Under normal conditions, it can only protect copper surfaces from further corrosion. In the high-temperature weld process, it is necessary to remove the protective film quickly and easily by using flux. It is an easy way to quickly and efficiently form a solid connection by combining the clean copper surface with the molten metal.

hasl vs lead-free hasl vs osp

This surface finish is a water-based finish that protects the copper until soldering. This coating prolongs the life span of copper by preventing oxidation. This coating is less durable on organic surfaces and more sensitive. This product has a very short lifespan.

OSP is a cost-effective surface finish. It is an easy operation that takes very little time. The coating does not affect the size of holes on the PCB. It has a flat surface and a good finish. It is perfect for areas where PCBs are handled with caution. It is durable.

2.4 Immersion Tin

Immersion Tin is a surface finish that does not contain any lead. This surface finish can be used for small parts. This surface finish is ideal for Fine Pitch Technology due to its flat and thin finish.

PCBs with a surface finish are not only affordable, but they also have their disadvantages. Tin can react and shorten the shelf life of PCBs by reacting with their copper layers. It is also important to use it as soon as possible because it is easily tarnished. It is very sensitive. You will see tin whiskers after a few weeks. All current solders are tin-based, so the tin can be used with any solder.

2.5 Immersion Silver

The price of immersion silver surface finish is reasonable. The finish is flat. Silver plating protects the copper from oxidation. The silver layer, although thin, is very conductive. The silver layer does not affect the size of the hole, which is perfect for Fine Pitch Technology.

This type of finish can tarnish easily. The silver layer tarnishes when exposed to air. Anti-tarnish packaging is used to prevent this. After removing it from the package, silver is extremely sensitive and must be soldered. Immersion silver has a moderate durability. It is also affordable and compliant with RoHS standards.

immersion tin vs immersion silver

Immersion silver is a process that falls between electroless Nickel and Immersion Gold and OSP. This is an easy and quick process. Even if the PCB is exposed to humidity or heat, it can still be soldered well. However, the PCB’s luster will fade. Immersion silver does not have the same physical strength as electroless Nickel/immersion Gold because it doesn’t contain nickel.

2.6 Plated old

Hard Gold is another name for Plated Gold. Surface finish is expensive because it adds a layer of gold to the PCB. The PCB is coated with a gold layer by electroplating. The circuit board is strengthened by the gold layer, which is tightly bonded. Gold is a superior conductor and offers a high-quality electrical performance. The gold finish also has a commendable resistance to oxidation. PCBs are ideal for this finish, since they can withstand high wear. The gold surface finish can last a long while.

This type of finish is expensive due to the extra processing needed. The thickness of the gold affects the price. As the thickness of the gold immersion rises, so does the cost. Processing surface finish is challenging. It is a rare material because of its high cost, but it has a great surface finish. Hard gold is not solderable.

2.7Electroless nickel immersion gold (ENIG)

ENIG is the most common ENIG due to its RoHS compliance and properties. The copper is coated with nickel and then a thin gold layer is placed on top. The nickel layer is soldered to the components and the thin layer of gold protects them until soldering has been completed. ENIG produces a PCB with a pure top gold layer. It is softer than gold electroplated. It is commonly known as “soft plating”.

plated gold vs enig

ENIG is durable and has a long shelf life. Due to the two layers, it is expensive. It’s thin, flat and has a smooth finish. This allows it to be used on smaller components. The black pad syndrome is ENIG’s sole problem. This is caused by the accumulation of phosphorus between the gold and the nickel layers.

2.8 Electroless nickel palladium immersion gold (ENEPIG)

ENEPIG’s surface finish prevents air reactions and corrosion. Its best feature is its long shelf life. This type of surface finish is made up of three layers of gold, palladium and nickel. They provide long-lasting performance when combined.

Unlike ENIG, there is no “black-pad” syndrome. RoHS compliant and lead-free. Its high price and complicated processing are the main concerns when using this product.

You can utilize more mixed processes in addition to the ones mentioned above. For optimal results, it is advised to combine two or three surface finishes. PCBs can have multiple finishes. ENIG+ OSP or ENIG+HASL is the most common surface finish.

The benefits and drawbacks of PCB surfaces are contrasted in this table.

3.The importance of PCB surface finish

PCBs are not complete without a PCB’s surface finish. Without it, copper surfaces that are exposed to air and moisture will quickly oxidize. PCBs can fail in a catastrophic way. Surface finish of PCBs also affects reliability, performance and lifespan.

It serves as a barrier to protect soldered components from exposed copper traces.

3.1 Protection from Corrosion

PCBs are susceptible to corrosion in humid or harsh environments. PCBs are protected by the surface finish. This can stop copper traces from oxidizing with time. Maintaining electrical integrity is vital.

3.2 Environmental Resilience

PCBs are susceptible to degradation by factors in the environment, such as humidity, temperature fluctuations and chemicals. You can increase the reliability of a product by selecting the right surface finish for each application.

3.3 Component Compatibility

This ensures the PCB surface level. It is necessary for fine-pitch components to be placed precisely. This increases the production and improves electrical conductivity.

3.4 Reflow Cycle Durability

Finishes should be able to withstand repeated exposure to heat for applications that need multiple reflow-soldering cycles. The reflow resistance of ENIG (Electroless Nickel Immersion Gold) is well known.

3.5 Lead-Free Compliance

Lead-free finishes are required by strict regulations to reduce the quantity of hazardous substances. An environmentally friendly choice is lead-free HASL or ENIG.

3.6 Connector Lifespan

In applications where connectors are regularly plugged in and disconnected, finish is essential. Gold hard or soft finishes provide premium durability and reliable connections.

3.7 Solderability

The term “solderability” refers to the surface’s ability to form strong and reliable connections during assembly. The finish of the surface has an impact on the soldering. The finish of the surface directly affects assembly efficiency and joint strengths.

3.8 Surface Flatness

A uniform, smooth surface is essential for fine-pitch and high-quality soldering. Surface flatness improves electrical performance and simplifies production.

8 Points of The Importance of PCB Surface Finish

4.The Key Factors in Selecting a PCB Surface Finish

When selecting a surface finish for your PCB, take into account the following factors:

4.1Cost Limitations

Cost influences your decision. Prioritize it. Hard gold is more durable but also more expensive. Consumers on a budget will find immersion silver to be a great choice. ENIG offers high performance, but at a pricey price. OSP has fewer features and is more affordable.

4.2Requirements for Lifespan

Some surface finishes last longer than others. ENIG and immersion Gold are more resistant to thermal cycling, environmental stress and wear than other finishes.

4.3 Environmental Compliance

Make sure that the finish meets industry standards. Lead-containing finishes, such as HASL, are not suitable for RoHS compliance.

4.4 Signal Integrity

In high-speed/high-frequency PCB design, we must first consider surface flatness and low signal loss. This time, immersion silver or gold is the best option.

4.5 Solderability

Reliable soldering is crucial for a high-quality assembly. HASL or ENIG are typically the best solder joints.

4.6 Storage Duration

Choose surface finishes that have a long shelf life, such as ENIG, immersion silver, or other surfaces with a high shelf life.

4.7 Specific Needs

Consider the PCB’s purpose. Components with fine pitches that need ultra-flat surfaces are best suited for immersion tin and immersion silver.

The finishes are different in each field. High-frequency applications benefit from finishes that minimize signal loss. Flat surfaces are important. Then, immersion silver will be the first choice. Hard gold is an excellent choice for connectors, which are often mated due to its high wear-resistance.

4.8 Operating Environment

Surface finish is determined by the application scenario for PCB. Before choosing, you should consider the extremes of temperature, humidity and the exposure to chemicals or gases. For harsh environments, you should select a finish with a high level of durability like ENIG or Hard Gold.

5.PCB Surface Finish FAQs

1)Which is better: ENIG or HASL?

ENIG is superior to HASL for fine-pitch components, but it costs more.

2)How do RoHS and REACH differ?

RoHS limits the use of hazardous materials in electronic devices.

REACH is an international regulatory system for chemicals that protects the environment and human health.

3)What is the best finish on PCBs for soldering?

HASL or ENIG is usually the best solderable material for strong joints.

4)What is the new technology in surface finishing?

Nano-coatings are a relatively new technology. They enhance PCB performance in modern applications.

5)What types of surface finishes are used for PCBs?

These include HASL (Halogenated Silver), ENIG (Intrusion Tin), Immersion Silver and OSP.

6)What’s the difference between ENIG and Plated Gold?

Plated gold is ideal for mechanical applications that require high wear resistance and where hardness is important. ENIG is perfect for high-reliability electronic components and fine-pitch soldering where flatness and solderability are important.

7)How should I handle and store PCBs with surface finishes?

You should store them at a specified temperature/humidity. Use anti-static packaging. Avoid UV exposure and follow the shelf-life guidelines provided by the manufacturer.

6.Surface Finishing in Orinew

Orinew Surface Finishing One of the top companies in China’s PCB manufacturing sector is Orinew. We follow stringent RoHS guidelines. We manufacture high-quality PCBs.

We provide a range of surface finishes that can be tailored to our customers’ unique requirements. The cost of PCBs and PCBA assemblies is competitive.

Do you’d like to know more? If you have any questions, please contact us.

OrinewPCB has focused as a one-stop PCB assembly manufacturer from PCB Manufacturing to Electronic Components Sourcing to PCB Assembly to Test to Program IC for more than 14 Years with reliable quality and fastest delivery for global clients.

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