The printed circuit board materials are composite, providing the supporting base upon which the etching of PCB traces and components occurs. A majority of PCB materials are reinforced epoxy resin substrate, glass fiber, and epoxy resin substrate bonded with copper foil.
When it comes to PCBs, copper is the most popular choice of material here. Copper is an excellent choice in terms of proper maintenance of charge. This article is all about PCB materials and the right type of materials for your PCBs.
(An engineer inside a PCB manufacturing firm)
A. PCB Materials
I.PCB Materials – How to make the best choice
1.PCB Material Types
Several types of PCB materials differ based on electrical, thermal, and physical factors. They include factors such as dielectric strength and constant, tensile strength, and thermal capacity. All these factors do determine a PCB’s ability to support certain functions and applications. The following are the most common PCB material types:
FR stands for Fire Resistant, while four stands for the four types of materials used. FR-4 content is one of the most used PCB materials consisting of a flame-resistant glass with a reinforced epoxy laminate sheet.
These have the same layout, just like any other PCB. However, it consists of layers of solder mask, copper, and silkscreen over it. It also includes a metal substrate as opposed to a plastic substrate.
Copper Clad Laminate (CCL):
The CCL is the base printed circuit board material under the solder mask. The Copper Clad Laminate comprises a thin layer made of a non-conductive substrate and a conductive copper foil that provides mechanical strength.
Rogers PCB Material:
These are generally associated with low electrical loss, more moderate dielectric loss, cost-effective fabrication, and a vast range of DK values. The Rogers material finds substantial use in the manufacture of PCBs.
(Having the right materials improves the overall quality of your PCB board)
2. PCB Material Properties
These are the properties of PCB material that are related to its ability to conduct heat effectively. On a PCB, significant thermal properties components include heat capacity, thermal stress, thermal conductivity, and thermal expansion.
Electrical properties for a majority of PCB materials stand at about 2.5 to 4.5. However, the dielectric constant varies with frequency and tends to decrease as frequency increases. Some PCB materials have very little change in relative permittivity compared to others.
3. PCB Material Selection Guide
Quality consideration is paramount when selecting PCB materials. Regardless of where your PCB will serve, the documents must have to meet the intended requirements. The board shouldn’t quickly fail due to physical stress. You will not compromise the original PCB's fundamental parts with durable PCB materials, especially when undertaking hardware updates.
The cost of PCB materials matters a lot. Many designers use either gold or solder tabs. However, gold tabs are a little bit expensive. When it comes to buried and blind vias, buried vias tend to be cheaper. Lastly, considering line and width spacing either above or below six mils, spacing above six mils does incur higher costs.
Power and Heat Considerations
Power and heat are some of the most critical factors determining the reliability and usefulness of a PCB. To be on the safe side, ensure that you check for your chosen boards’ thermal capacities.
(Take into consideration the quality, cost, and power of the materials of our PCB board)
II. PCB Substrate Materials – What Type is Right for Your PCB?
The materials that you select for your PCB will have an impact on the functionality of your product. Going for the best PCB substrate materials can broadly impact durability, performance, and plenty of other board features. Here is how to go about selecting the best materials for your board.
1. Copper Foil Requirements
Have you ever come across the term HDI PCB? If not, then it means High-Density Interconnect Printed Circuit Board. PCBs require copper foils for practical functionality. A copper foil is a harmful electrolytic material that you can find on the circuit's base layer. The copper foil acts as the conductor of a printed circuit board.
1.1 How Surface Roughness Can Affect the Quality of Your PCB
If you want to have a proper PCB, you must consider matters to do with the copper foil surface's roughness. Roughing ensures that the conductors have peel strength and that the copper foil's bonding and the substrate material is optimal. Nowadays, the standard roughness stands at around 5μm. To boost the peel strength, you may have to embed a hump on the foil into the substrate to ensure that the severity stays as low as possible.
2. Insulating Dielectric Laminates
The buildup process is an essential property of HDI PCBs. In case you resort to using resin-coated copper or use a combination of copper foil lamination and prepreg cloth of epoxy glass, you may design a beautiful circuit.
Today, manufacturers implement SAP and MSPA technologies. Such has brought about a generation of copper conduction planes by applying chemical copper plating with insulating dielectric film lamination. The thin copper plane is the main reason why manufacturers can produce beautiful circuits.
2.1 Why Lamination Dielectric Material Is Crucial for SAP
If you are going to design HDI PCBs, then you need to factor in lamination materials and its requirements. You need to factor in include thermal capacity, dielectric performance, bonding, and insulation.
In multi-layer PCBs, the substrate materials should be in a position to help in the reduction of thermal expansion coefficient in addition to dielectric property while at the same time, securing optimal resistance to heat. These properties make the right choice of substrate material since they can achieve the entire performance goals at an acceptable cost.
When the space and width of circuits are below 10μm, there’s no option but to use SAP technology when manufacturing them. In large scale production, MSPA technology comes in to use thin copper foil to insulate dielectric lamination.
3. Why High Speed and High Frequency Are Important for Your PCB
Technology continues to evolve every day, with innovations such as wireless connections, high frequencies, and high speeds being apt examples of the latest technological innovations. High-speed designs are the topic of almost every expert in the industry.
There’s a possibility of making a difference between:
Medium Dk/Df laminate PCBs have Df that’s no higher than 0.010, and Dk of a maximum of 4.
Low Dk/Df laminate PCBs – have a Df of less than 0.005 with a Dk of not more than 3.7.
3.1 Types of Substrate Materials usable in High-Frequency PCBs?
You can find the best materials to use in one of the following:
- Fluorine-series-resin – materials such as PTFE consist of the best dielectric performance and a great choice, especially if you require at least 5GHz frequency. While they are a bit costly, they are the best since they have a high thermal expansion coefficient.
- PPE and PPO resin – it’s a suitable option for 1-10GHz frequencies. These secure an excellent all-round performance of your PCB.
- Modified epoxy resin – these are an excellent choice for frequencies between 1GHz and 10GHz. Generally, they are affordable and a reason as to why they are so popular.
4. Thermal Requirements of PCBs
As a component carrier, a PCB is the main component aimed at achieving coherent thermal management. In advance, designers have to factor in the following primary thermal considerations:
- Available space and mounting peripherals
- The amount of heat and power loss
- How to conduct heat to the radiator
- Heat sources on the PCB
- Reliability requirements, such as cycle stability
- Application temperatures and ambient temperatures
(Designers need to consider the thermal requirements when looking for PCB substrate materials)
4.1 What Would Material Be the Best Choice for Heat Conductivity?
When you want to combine excellent heat conductivity, optimal cost, and availability, the material’ must be aluminum. While aluminum tends to be cheap, it can also bring about an excellent electrical connection while ensuring that everything is solder and lead-free.
5. How to Choose PCB Substrate Materials
There are three different PCB choices that you can pick; rigid, flexible, or flex-rigid PCBs. The goal is to choose a board that will be perfect for your product. Many people go for compact shape and size, though they forget about performance.
Polyimide is a smart choice since it’s versatile and can fit into different categories, such as black, transparent, and white. Additionally, it ensures that there’s a low thermal expansion coefficient and, at the same time, maintains adequate resistance to matters concerning heat.
Mylar substrate tends to be highly elastic in addition to having excellent resistance to several environmental factors. Additionally, it’s relatively affordable, a reason as to why a majority of users use it.
For flexible boards, polytetrafluoroethylene and advanced polyimide substrate are the best type of material to use—flexible PCB used in many industries, such as smartphones, gadgets, and the medical industry.
6. Where to Manufacture PCBs?
Are you having a difficult time selecting the best PCB manufacturer? Don’t be troubled. OurPCB is the best choice for manufacturing and assembling PCBs. We have more than a decade of experience and have more than 2,500 clients throughout the globe at the moment.
Our engineers are skilled, experienced, and use state-of-the-art equipment to meet clients’ needs. With us, you can have custom-made boards. Do you need rigid or flexible PCBs? We can make your desired board type for you the way you want.
III. Aluminum PCBs – Five Things You Need to Know at First
PCBs consist of several metals and aluminum is one of them. Aluminum PCBs are the most popular metal core printed circuit boards (MCPCBs) in the market. That’s the reason as to why they find use in plenty of applications today. This section is a detailed discussion about aluminum PCBs.
1. The Evolution of Aluminum PCBs
In the 1850s, the first PCBs hit the market with metal strips and rods connecting significant electrical components on wooden bases. Over time, wires connected to screws began replacing the chassis and metal strips in the wood bases.
With rising demand, Charles Ducas manufactured a stencil consisting of conductive inks. It could “print” some of the most impressive electrical paths on insulated surfaces. In 1925, he submitted a patent that gave rise to the phrase “printed wiring” and “printed circuit.”
The 1970s witnessed extensive use of aluminum PCBs with recent years seeing a spike in aluminum PCBs, especially in the LED industry. Today, almost all electronic components manufacturers rely on aluminum PCBs based on several advantages that they offer.
2. Advantages and Disadvantages of Aluminum PCBs
Compared to other PCBs, aluminum PCBs have many advantages.
Here are some of its benefits:
- They are cheap – compared to different types of metal, aluminum tends to be less costly. Additionally, it can withstand several climatic conditions, meaning that it’s easy to mine and refine it.
- Environmentally friendly – besides aluminum not being a toxic metal, it’s highly recyclable. It brings about a healthy planet.
- Impressive heat transfer – high temperatures bring about massive damage, especially in electronic components. However, aluminum is an excellent material for conducting and transferring temperature or heat to reduce the PCB cost.
- Lightweight and durable – aluminum is lightweight, durable, and thin metals compared to ceramic and fiberglass.
- Heat radiation – aluminum PCBs are also excellent when it comes to heat radiation and better strength.
2.2 Disadvantages of Aluminum PCBs
- While there are plenty of advantages, there are a few advantages worth noting with aluminum PCBs.
- First, the manufacturing process of aluminum PCBs is a bit unique compared to other types of PCBs.
- Secondly, it’s not possible to manufacture double-sided PCBs using aluminum metal. The current mainstream available in the market can manage to do only single aluminum PCBs.
- Third and last, there’s a high chance of aluminum PCBs encountering electrical strength and pressure issues, though not that much.
3. Manufacturing Process of Aluminum PCBs
The manufacturing process of aluminum PCBs is a little bit unique. The difference that separates conventional PCB manufacturing from aluminum PCB manufacturing is only the chemical milling step. When manufacturing an aluminum PCB, you need to carefully add a fragile layer of dielectric between the circuit and base layers.
After adding the dielectric layer, you have to etch the copper foil. Etching allows you to come up with a pattern that you want. As you can see, the manufacturing process of aluminum PCBs tends to be a challenging undertaking.
(An aluminum PCB that bears LED lights)
4. Types of Aluminum PCBs
There are several types of aluminum PCBs as mentioned below:
- Through-hole Aluminum PCBs
- Flexible Aluminum PCBs
- Hybrid Aluminum PCBs
5. Applications of Aluminum PCBs
Aluminum PCBs find applicability across several forms, especially in places or conditions with high heat dissipation needs. Most commonly, they are usable in the following areas:
- General lighting
- Traffic lights
- Motor controllers
- Automotive applications high-power scanners
- Signal beacons
- Power converters, automotive dashboards
IV. Fr1 PCB–8 Differences in FR1, FR2, FR3, and FR4 Materials
PCBs’ composition is different materials, such as FR1, FR2, FR3, FR4, and plenty of other elements. But what is the difference between these materials? Below is a brief explanation of the differences.
1. FR4: The Most used Type of Material
FR means Flame Retardant. FR4 is the most popular material among PCB designers and ideal for passing through-holes. It’s ideal for manufacturing PCBs of all layers. Additionally, it’s suitable for applications that require regular flexing.
2. Differences in High-temperature Resistance
Depending on different conditions, PCBs will require different types of materials. For instance, materials used in military applications aren’t the same as those in electronics. Some materials are ideal for high-temperate conditions while others aren’t.
3. The Material Composition of the Main Combination
Material composition is a huge differentiating factor between all the FR PCBs since there are several materials. FR1, FR2, FR3, and FR4 materials do differ based on electrical heat strength, heat resistance, and thermal properties, among others. For instance, FR3 content consists of the epoxy resin binder, while FR2 consists of phenolic resin.
While producing PCBs, some materials tend to be cheaper than others. Costs are a huge factor that may affect the final price of a PCB. A lot of PCB producers prefer using FR4 material since it's cost-effective.
5. Differences between FR3 and FR2
There are notable differences between FR2 and FR3 materials. For instance, thick paper and phenolic resin are the material you’ll find in FR2. Additionally, FR2 is suitable for one-layer PCBs as they are ideal for passing through-holes.
6. Materials Suitable for Through-hole Technology
Plenty of PCB designers who try to use FR1, FR2, and FR3 materials and subsequently subjecting them through thru-hole don’t get the expected results. However, those who use PCBs made of FR4 find the best results, meaning that FR4 material is the best in through-hole technology.
7. Materials Suitable for Multilayer Boards
Manufacturers can use FR1, FR2, and FR3 materials to manufacture PCBs. However, plenty of them prefers using FR4 equipment. PCBs with FR4 materials are stable and reliable.
8. A unique introduction to FR4 Materials
FR4 is one of the most popular materials when manufacturing PCBs. FR4 materials are durable, cost-effective, and moisture-resistant. They are also lightweight and consist of high dielectric strength. It doesn’t absorb water and consists of the best electric loss properties.
B. PCB Surface Treatment Method
I. PCB Tinning – How Can I Get the Best Effect on the PCB?
Copper is a frequent conductor that uses PCBs since they maintain a proper charge to correctly power the PCB. But when unprotected, it may oxidize. However, with PCB tinning, there’s the avoidance of such a scenario.
(A close up of a PCB that has undergone tinning)
1. PCB tinning
Tinning involves coating copper traces using tin layers to prevent them from oxidizing, degradation, or corrosion. Tin plating also helps in protecting critical components during etching.
Benefits of PCB tinning
PCB tinning simplifies the whole manufacturing process while preventing unwanted etching. PCB tinning is also ideal when there’s the involvement of a high current path bridge. PCB tinning also simplifies the risk of corrosion on a printed circuit board.
Is it possible to do PCB tinning from scratch?
Contrary to popular belief, it is possible to do PCB tinning from scratch. It requires effort and some knowledge in chemistry to form tin. PCB tinning is the same as manufacturing PCBs from scratch with the combination of the best materials. Before exploring the PCB methods from scratch, it’s useful to understand the PCB tin plating process.
2. The PCB Tinning Process
How to do PCB tinning
PCB tinning utilizes tin. The question is how to use this tin to mask the copper traces in a PCB. The tinning process uses pure tin, though it uses a soldered container. Soldered tin is a mixture of tin and lead, mixed at the rate of 40:60 ratio.
The electroplating method of PCB tinning
There are plenty of means to tin a PCB physically. However, electroplating is one of the most common methods. After the production of a PCB, the second coating of tin follows. For you To create the second coating of tin, more soldering is a necessity. Like copper, tin oxides the moment it gets exposed to external environments. Applying solder masking ensures that the circuit board doesn’t oxidize.
3. PCB Tinning Solutions Material Composition
Tinning solutions consist of several materials. Some of these materials are some of the everyday items that you can purchase locally. To ensure that your PCBs are the best, you need to source materials from PCB tinning specialists.
Not all of these materials are required to make a tinning solution. However, you need to choose the best tinning solutions. Since plenty of variables go into tinning solutions, there are several ways to develop PCB tinning solutions from select materials.
Thiourea - The essential ingredient for PCB tinning
Thiourea is one of the essential ingredients for PCB tinning. Thiourea is a combination of plenty of materials to create a tinning solution. Without extracting thiourea from silver polish, then making tinning polish from scratch isn’t easy. Thiourea is an active compound. It’s one essential ingredient when it comes to PCB tinning.
Other ingredients that will assist in creating a tinning solution
Besides thiourea, other elements can assist in creating a tinning solution. Some of these materials include hydrochloric acid, also known as muriatic acid. Solid lead-free is also another ingredient best for the creation of a tinning solution.
Create the skills needed for tin plating solutions
Some skills are necessary during the creation of tin plating solutions. While some “experts” may lie to you that creating tinning solutions don’t require any skills, this isn’t the case. You’ll need some knowledge and skills. For instance, you’ll require the necessary chemistry skills to manufacture your PCBs and tinning solutions.
4. DIY PCB Tinning
PCB tinning isn’t a complicated process, provided you have the right materials to undertake the whole tinning process. You need to take a couple of precautions if you decide to develop a tinning solution yourself and the go-ahead to apply it to your homemade PCBs. The following are some of the essential things to factor in when you want to develop a tinning solution.
Things to watch out for
When it comes to PCB tinned, must take certain precautions. There are some dangers that you may want to watch out for at all times.
How much does it Cost to do DIY PCB Tinning?
Costs matter when it comes to DIY PCB tinning. For instance, you can purchase silver polish for around $10. In its natural solution state, you can buy thiourea for a little over $50. If you intend to do PCB on your own, be prepared to spend slightly over $100.
5. Is PCB Tinning Necessary?
PCB tinning reduces pressure and prevents copper on the inside from oxidizing. Additionally, tinning ensures the longevity of your PCBs. Moreover, PCB tinning enhances current along the PCB tracks, allowing it to operate and perform consistently.
II. PCB Copper Weight – The Ultimate Guide to How to Apply Perfectly
PCBs are some of the most complicated electronic components, especially when it comes to issues concerning weight. Copper is the primary material here, and it’s a bit tasking to measure and calculate the value of copper. This section focuses on PCB copper weight.
(Copper details on a printed circuit board)
1. What is the PCB Copper Weight?
It’s simple; this is the overall weight of the copper material used in the PCB. There are plenty of factors that may contribute to the importance of copper in a PCB.
Copper is an alloy
Copper is an alloy, which makes it a conductor and the most common in PCBs' manufacture. The grade and the form of copper determine the weight of the PCB. The worst thing is the application of copper to a circuit board following some unclear calculations.
2. Design Considerations with Heavy Copper
Heavy copper is as thick as 19 ounces per square foot. Lately, the use of heavy copper seems too familiar and widespread. The reason for this is because it gives more options when designing a PCB. Heavy copper is also versatile during PCB production.
3. PCB Copper Weight Specifications
This section touches on three specifications regarding copper weight. There are three crucial “weight classes of copper” worth noting, as seen below:
Any copper plating that is ¼ of an ounce per square foot to 4 ounces per square foot falls under the category of standard copper. Standard copper has a very low risk-failure of when plating a PCB using it.
All copper that’s 5 to 19 ounces per square foot falls under the category of heavy copper. While it’s difficult to manufacture them, they are superior to standard copper.
Every copper that’s 20 to 200 ounces falls under the category of extreme copper. Until a decade ago, testers agreed on the possibility of using EXTREME copper in a PCB.
4. PCB Base Weight vs. Copper Plating Thickness
You’ll determine plating thickness the moment you heat or cold copper to certain levels. Sadly, manufacturers fail to factor in trace and temperature when determining the width of the plate. Here, we explore the copper plating process and how to calculate copper weight effectively.
5. How is the Weight of the PCB Copper Finalized? - The Copper Weight Calculator
Copper and copper alloys have their grades. Grades of pure copper begin with “C” followed by some digits. Many manufacturers use C110 grade copper. The shape of the copper also matters a lot. Round bars are the best.
6. Heavy Copper and EXTREME Copper in PCB Design
Heavy and EXTREME copper is the best during PCB design. During soldering, they perform well without causing any detrimental effects on the PCB. Additionally, they also last longer and make the creation of PCBs a little bit complicated.
How copper weight impacts PCB manufacturing
Copper weight impacts PCB manufacturing in several ways. For instance, it amounts to an efficient PCB in addition to a better-looking board. Additionally, it’s cheaper and faster to manufacture heavy and EXTREME copper compared to standard copper.
III. 13 Advantages of Plating Immersion Gold PCB
There are advantages of immersion gold PCB worth noting. Below are 13 of such benefits:
1. Easy to Process Structure
A significant advantage associated with it is that it’s a very natural mechanism to carry out. It’s a straightforward process requiring no complicated technicalities.
2. Flat Surface
ENIG is the best solution when working with complicated surface components and lead-free requirements that require a flat surface, such as flip chips and BGAs. But the ability to fit into a flat surface is a significant advantage of ENIG.
3. Good Oxidation Resistance
ENIG surface finishes are excellent when it comes to oxidation resistance. ENIG surface finishes contain a covering of nickel plating consisting of thin layers of immersion gold that protect nickel from oxidation instances.
4. Good electrical performance
When it comes to surface finishing, ENIG or immersion gold are the best choices. The reason is that they provide excellent electrical performance.
5. High-temperature Resistance
Especially those that go into medical and military applications, PCBs must withstand high-temperature conditions for ENIG vs. HASL. It is best to resort to ENIG finish as such can withstand high-temperature conditions.
6. Long Service Life
The type of finish that manufacturers use in PCBs manufacture will determine the board's shelf life. ENIG PCB finishes are the best for the long service life of PCBs.
7. Suitable for untreated Surfaces
As a designer, you would want to protect untreated surfaces that tend to oxidize immediately if left untreated. ENIG is suitable in untreated surfaces such as membrane switches and contact points.
High exposure to lead may bring about health complications or even death. As a manufacturer, there will be no exposure to harmful chemicals if you use immersion gold as a surface finish on a PCB.
9. Suitable for PTH
Plated through-hole parts consist of wires that come out of the bottom teams' sides, allowing designers to stick them onto a breadboard and solder them effectively. Another notable advantage when it comes to ENIG is that it’s ideal for plated through-hole.
10. ENIG does not require electroplating
ENIG doesn’t require external sources of power to deposit coatings of metallic on the base material.
11. Easy to Weld
ENIG is slightly softer compared to Gold plating. Welding ENIG doesn’t bring about welding defects, unlike ENEPIG or HASL.
12. ENIG Meets all RoHS Requirements
RoHS guidelines prohibit using 10 of the most poisonous substances in the manufacture of electronic and electric devices. Fortunately, ENIG meets the fundamental requirements of RoHS.
13. ENIG PCB Finds use in a variety of Electronic Products
ENIG finds applicability in various electronic products such as medical appliances, wearables, and computer motherboards, to mention but a few.
( Green PCB with gold finishing)
IV. 10 Differences between HASL and ENIG Plating Methods
There are plenty of differences between HASL and ENIG plating methods. Here are the ten differences between the two.
1. The Advantages of HASL
HASL is budget-friendly since it’s possible to detect potential surface cover issues before the board's assembly of components.
HASL is one of those durable coatings that prevent copper from corroding.
Easy to work with
HASL surface finish is natural to run as it presents perfect wetting throughout the whole process.
HASL finish, unlike other types of finishes, comes in several variants and very easy to access.
2. The Advantages of ENIG
Several advantages come with ENIG. For instance, ENIG works well with flat surfaces in addition to its ability to withstand tight tolerances. Additionally, it’s also lead-free, durable, and comes with excellent electrical skills.
HASL vs. ENIG
There are notable differences between HASL and ENIG. Factors such as shelf-life, operation step, and surface finish differentiate the two. Here are the differences between the two:
3. Cost Difference between HASL and ENIG
While HASL remains a popular surface finish based on the fact that it’s cheaper than ENIG, ENIG also does well when it comes to corrosion resistance.
4. HASL and ENIG Have Different Operation Steps
HASL and ENIG differ in terms of their operation. For instance, unlike ENIG, HASL requires a series of compressed hot-air knives to remove excess solder.
5. HASL and ENIG Service Life
Unlike ENIG, HASL isn’t durable. It’s not suitable for applications that need bending and minimal shock.
6. Differences in Surface Treatment between HASL and ENIG
HASL comes with an uneven finish, unlike ENIG, which has got a smooth surface finish.
7. Selection of Thin and Thick Plates
ENIG plates have a typical thickness of 5-15 minimum gold, an aspect that makes them easy to solder. On the other hand, HASL board thickness goes up to 200 mils, making them slower in electric conductions when con.
8. The Difference between Unleaded and Leaded
Both HASL and ENIG exist in different variants. HASL can either be lead or lead-free. On the other hand, ENIG can either be high-quality or low-quality.
9. Differences in Bonding Strength between HASL and ENIG Plating
HASL does well with hand soldering as the joints tend to form quickly. On the other hand, ENIG plating boards must undergo coating using gold and nickel to achieve the desired bond.
10. Solderability and Corrosion Resistance
HASL finish brings about PCBs with some of the highest levels of solderability. On the other hand, ENIG finish offers impressive oxidation resistance to protect the copper from corroding.
C. PCB Via
1. PCB Via- Types
Unlike before, when we had PCBs that only utilized a single side, now PCBs use both sides, as you’ll learn below.
(A plated through-hole board)
PCB-via’s three basic types
There are three types of PCB via namely
- blind via
- plated through-hole
Through-hole vias are the most commonly used, followed by blind via boards. Buried vias connect the inner layers of a commission. Hence the name buried vias.
2. Blind Via PCB-What Should You Know (Latest introduction)
Via is a requirement needed to make the necessary connection between the layers. Here’s what you need to know regarding
Blind via PCB
As noted earlier, designers can choose to buried, through-hole, or blind vias during PCBs' design. Blind via PCBs consists of those boards that connect the outermost layers to the inner layers.
3. Tenting Via – The Ultimate Guide to the Importance of PCBs
Vias are necessary on PCBs for purposes of establishing connection patterns between several layers of multi-layered boards. But what are tenting vias? Do they have any importance at all? Here you can get the answer.
1. What is Tenting Via
Tenting via is the covering of via with some solder mask to the skin or enclose over the opening. A via is a hole drilled into a board, allowing multiple layers to connect. Tenting reduces the chances of shocks and electrical shorts.
1.1 What is Plugging Via
Via plugging involves filling the vias with resin or closing it using fills or a solder mask.
1.2 Tenting Vias VS. Plugged Vias
Tenting vias uses a solder mask to cover the vias using procedures such as spray or screen coating. When it comes to plugged vias, there’s the plugging of vias, mainly by using a solder mask or other non-conductive material.
2. Solder-Filled Vias
2.1 Copper Filled Vias
To come up with copper-filled vias, manufacturers fill through-holes using copper and epoxy resin. Copper-filled vias make PCBs more suitable for some specific applications. Copper-filled vias also consist of other capabilities that other conductive fillings can’t provide.
2.2 Conductive Vs. Non-Conductive Filled Vias
Conductive via fill is a material containing a silver-coated copper particle filled with epoxy matrix to provide thermal and electrical conductivity in a cured state. They conduct heat effectively.
You may think that non-conductive fills can’t make electrical signals pass through the via effectively. However, this is a big misconception. Non-conductive fillings are the same as mask plugged vias.
2.3 Solder Mask Over Vias
Vias consist of many materials, solder mask being one of the most common ones. During assembly, engineers apply a solder mask over vias. The ink used during solder masking pr gets hardened by exposing it to UV light as the material is UV sensitive.
2.4 Vias Plated Shut with Copper
This method is popular in military equipment and older legacy. Unfortunately, there are some limitations here. For instance, it’s a bit challenging plating the whole barrel smoothly and using many copper material.
3. Better PCBs in Eagle
3.1 Eagle Trace Width
In designing PCBs, trace widths are essential considerations as they determine the amount of current that will pass through the PCB without overheating and damaging it. Luckily, you can set trace widths in your Eagle design by altering the width and accessing such a diameter problem.
3.2 Eagle Via Size
The default via size in Eagle is 0.6mm. However, you can change such depending on your application and project.
3.3 Eagle Design Rules
Design rules in Eagle software let designers set values and design parameters of PCB designs. Designers can select or change design rules, however much they like.
3.4 Eagle Design Rule Check
The Eagle Design Rule Check enables designers to validate their PCB designs under the production process's physical limitations.
4. Vias Not Covered
These are vias lacking solder mask on the via barrel and the annular ring.
- Ideal for high-current traces
- It’s possible to do onboard testing by having easy access to both sides of the board.
- Vias can easily rust when left exposed.
- There’s a significant probability in the occurrence of shorts.
- Solder splashes and solder shorts can occur during wave soldering.
5.Via in Pad
Via in Pads offers some benefits over blind holes or through-holes as they bring about improved precision. Via in Pads is also efficient when it comes to heat dissipation and making excellent thermal management. It also provides an even surface and minimizes the PCB area.
Via plugging is a necessity if you want to tent holes connecting different layers of a PCB ultimately. Mostly, engineers use non-conductive such as solder mask, to promote the vias. Others prefer conductive fills such as copper to undertake via connecting.
D. PCB Etching
I. PCB Etching-How to Achieve the Perfect PCB Etching
PCB etching is a task better left to experts. If you do it wrong, then you may end messing everything up completely. But again, etching PCBs is a task that you can do from the comfort of your home. Here’s how to go about achieving perfect PCB etching.
(How to make the ideal etch)
1.Materials and Necessary Tools
Some of the materials and tools that you’ll need include
- a laser printer
- drill machine
- cloth iron
- steel wool
- permanent marker
- soldering iron
- glossy paper
- Ferric Chloride
2.Steps to DIY PCB Etching
Step 1: Take a circuit board layout printout
Use a glossy paper and laser printer to do this while ensuring you do the printout on the bright side of the article.
Step 2: Carefully cut the copper plate meant for the circuit board
Do this by using either a hacksaw or a cutter. Use sandpaper to get rid of the top oxide copper layer and photoresist.
Step 3: Make a transfer of your PCB print onto the plate of copper.
Sketch the copper plate using a pencil then use a permanent to trace over it.
Step 4: Onto your PCB plate, iron the circuit from the paper
To achieve this, you need to place the photo paper and the board on a clean wooden surface. Hold one end of the article using pliers to keep it steady before putting the hot iron cloth on the other end. The heat from the iron will transfer all the ink on the glossy paper to the copper plate. Remove the form gently by peeling it.
Step 5: Etching the plate
First, put on the rubber gloves. After that, place pieces of newspaper on the bottom to avoid spillover cases. Secondly, find a plastic bowl, fill water into it and dissolve 2-3 teaspoons of ferric chloride powder. Third and last, dip the PCB into the etching solution for three minutes. Remove the unwanted copper, a process we call etching.
Step 6: Cleaning and final touches
Get rid of the etching solution and other unwanted products in the right way. Be mindful of the environment.
3.Safety Measures While Undertaking PCB Etching
Safety is paramount when undertaking PCB etching. When doing this exercise, ensure that you put on protective equipment such as gloves, a lab coat, and protection glasses. Additionally, ensure that you have a first aid box, eyewash station, and emergency numbers.
4.Challenges of Creating/building PCB By Hand
Several challenges accompany PCB etching by hand. For instance, such may end up being a lengthy process. Secondly, etching mistakes are bound to happen quickly. Lastly, it may be hard to come up with the desired board that will function as intended.
II. 10 Disadvantages Must Consider if You Want to PCB Etching at Home
While PCB etching at home is fun, below are some of its disadvantages:
No Professional PCB Etching Equipment
You may lack essential equipment such as gloves or Ferric Chloride at home, an aspect that may make the entire process futile.
PCB Etching Reagent Time and Temperature Control
Etching reagents must stay at certain specific temperatures, a challenge that you’ll mostly encounter when etching at home.
It is easy to lose the gloss of the PCB surface.
By seeking experts' services, you stand a high chance of getting PCBs that contain high-quality gloss finish.
Etching PCB and PCB Related Functions
PCB is in direct relation with the function of the board. Unfortunately, etching at home doesn’t seem to consider such.
PCB Etching Complex Process
When done wrong (mostly at home), you may damage your board since etching is a complex process that is better left for professionals.
Thickness to control
Undoubtedly, it’s hard to determine the required depth when etching at home. Weight, flexibility, and impedance matching is an exercise better suited for experts.
Carcinogens Produced During PCB Etching
Etching PCBs requires the use of chemicals, most of which may be harmful. When etching at home, there might be no better way of taking precaution measures.
Shortened product life
Most of the time, etching PCBs at home will produce goods that won’t last long, probably due to substandard materials.
PCB Etching Process reworks hard
Reworks are challenging when you try them at home. You may lack the necessary equipment to do a repeat job if errors occur.
The use of inferior technology is self.
Explanatory; manufacturing experts use the latest technology compared to that that DIY enthusiasts employ.
E. Manufacturing Defects
I. 10 Reasons for PCB Manufacturing Defects and How to Eliminate Them
The need to ensure that faults are at an all-time low is crucial is essential during the manufacture of PCBs. Briefly explained below are the ten most common PCB manufacturing defects and how to go about eliminating them:
Plating Hole Defects Manufacturing Of PCB
Incorrect copper deposition creates voids and leaves gaps where copper etching lacks. You can avoid this by thoroughly cleaning your PCBs.
Lack Of Solder Mask Between Pads
It is another problem during PCB manufacture. You can avoid such by changing the design rules and reducing solder mask reliefs.
Electromagnetic Compatibility Issues In Cheap PCB Manufacturing
You can avoid this by ensuring that you minimize the circuit's contact area or choose advanced PCB production.
Burned Circuit Defects In Cheap PCB Manufacturing
To avoid this scenario, ensure that there’s adequate space between the components for better air circulation.
Chemical Leak Problem In Manufacturing Of PCB
Clean your boards thoroughly and check for any fluids left over during the production process.
The Problem Of Substrate Size In PCB Production
Without the right measurements, you’ll end up with the wrong substrate size. Ensure that your manufacturer gets all the measures right before production begins.
Changes In Bending And Warping In SMT PCB Manufacturing Process
It’s frustrating when you have to deal with bent PCBs as you may destroy essential components attempting to restore it to its original form. The following are reasons for changes in shape and what you need to do.
Some reasons for shape changes:
Some of the reasons for changes in shape include low substrate curing, different thickness of copper foils, and boards that cool quickly after hot melting them.
Solve the problem:
To solve such, ensure that the board is slightly thicker and evenly distribute copper on the panel with the same density.
Problems With Drilling In Cheap PCB Manufacturing Services
Here, you need to ensure that you use high-quality drills. Also, re-sharpen the drill bit before using it. You may also want to replace the drill bit in case of fracture.
Defects On Copper Substrate Surface In Low Volume Cheap PCB Manufacturing
You can solve this problem by increasing the adhesion between the copper surface and removing the converted layer if need be.
PCB Board Has White Spots
The only solution here is a thorough cleaning. Begin with wetting, followed by scrubbing, then rinsing, and finally, drying.
(A defective PCB board)
II. 7 PCBA Manufacturing Defects and Solutions
There are several PCBA manufacturing defects and solutions worth noting. Below is a discussion of the seven most common ones:
PCBA Manufacturing of Wire Breaks Problem
It is a standard PCB assembly defect that manufacturers can avoid by undertaking thorough wire inspection.
(A broken down PCB)
Pin and Connector Checks
It is another problem that manufacturers can do away with using a pattern-matching tool to ensure all the connectors' correct placement.
PCBA Manufacturing Open Solder Joints
Solder is a big problem in the assembly of PCBs. Fortunately, manufacturers can do away with this by using the right design during component placement.
Missing Parts (Component shift)
To eliminate such cases, you need to ensure that you maintain the right humidity and temperatures while minimizing rapid movement during assembly.
PCBA Manufacturing Heat Dissipation Analysis
The solution to this problem is to solder the SMD heat sink properly, especially high-power parts.
PCBA Manufacturing Shorts
Manufacturers avoid solder shorts by employing the necessary design rules in addition to using skilled stencil modification.
Chemical Fluid Leakage
To avoid chemical fluid leakages, manufacturers must ensure that they undertake proper cleaning of their boards.
III. 11 Easy Steps You Need To Know To Avoid Solder Balls in SMT Manufacturing
There’s nothing more frustrating than manufacturing PCBs only to find that they contain solder balls in them, some which may fall and cause shorts. So, how do you go about avoiding them during SMT production? Below is a brief discussion about such.
PCB Has Moisture
PCBs tend to retain moisture, especially when manufacturers store them in humid conditions that bring about water retention.
Manufacturers need to be mindful of storage and keep them in dry environments to avoid such problems. Also, the holes' thickness has to be large enough so that they don’t trap water.
Too Much Flux in Solder Paste
Flux ensures that metal parts of a PCB don’t oxidize. The change also improves amalgamation for soldering.
To avoid such a scenario, you shouldn’t use too much paste. Always use the right quantity and the proper flux for your application.
Improper Preheat Temperature
With improper preheat temperature, rest assured of facing the occurrence of solder balls on your PCBs.
All you have to do here is raise the temperature by 1.5 - 2 C while maintaining it up to 150 C. But don’t increase the temperature rapidly as such may bring about thermal damage.
Problems in Solder Paste Printing
The leading cause of such a problem is unclean stencils making solder paste to form solder balls.
It’s easy to avoid this problem. All you have to do is to set a zero gap between the printed template and the PCB. Additionally, you need to put the squeeze print pressure to the very minimum.
Missing Solder Mask Between Adjoining Pads
This error is another common mistake in SMT manufacturing, an aspect that can bring about solder balls.
It’s simple. All that you have to do is to apply the solder paste evenly on the PCB. Additionally, a slow preheat temperature rate is essential as such will assist in spreading the solder paste evenly on the surface of the PCB.
Improper Pad Spacing
Improper pad spacing may lead to a board's reduced functionality since it may bring about solder balls, which may bring about shorts.
A PCB design solution is the best answer to this problem. Additionally, you may want to program everything in the right manner to avoid cases of improper pad spacing.
Residues Left on PCB Surface and Pads
More often, after getting your batch, you may find that there are some residues left on the surface of the PCB or pads, an aspect that may lead to solder balling.
Try and clean your PCBs the moment you receive them from your manufacturer using professional solutions.
Issues with Stencil Dimensions
Thick stencils hamper soldering and bring about the formation of solder balls.
Go for the right thickness of the stencil. Don’t select very thick stencils for your project.
Misalignment of Solder Paste Printing or Components
Misalignment of components is a significant problem in SMT manufacturing. It leads to the reduced functionality of the board and solder balls.
(Misaligned solder paste)
Ensure that you are keen on how you place the components on your boards. Double-check to ensure proper alignment before component placement.
Improper Placement Pressure
The mounting pressure will determine the outcome of your boards. Don’t use too much trouble as such will bring about solder balls.
You need to set the right amount of pressure by determining the appropriate strength to apply after careful assessment of the PCB components. Don’t use much trouble, and remember to adjust the power of pick-and-place nozzles.
Solder Paste Oxidation
Solder paste is prone to oxidation, an aspect that may bring about solder balls.
Use the recommended solder paste for SMT production. Besides following handling guidelines, ensure that you keep the solder paste in a cool place.
We believe that you are well versed in almost everything to do with PCB manufacturing, its challenges, and what to do when faced with manufacturing challenges. Are you in need of PCB manufacturing and assembly services?
If so, you can get in touch with us via email. We can discuss some problems with PCB together and help you solve the difficulties encountered.