Manufacturers use different kinds of materials for cladding PCBs. However, copper is a common material used for cladding PCBs. With the development of high-density electronic devices, heat dissipation is a major concern.
Copper is a good conductor of electricity; hence, it is ideal for this purpose. Copper clad boards prevent overheating in several electronic devices. The electronic industry has continued to develop; hence, copper clad boards are common. In this article, we will shed more light on copper clad PCBs and their importance in today’s electronics.
What is a Copper Clad PCB?
A copper clad PCB is a type of PCB that features a copper clad laminate. This laminate is a PCB substrate that plays a significant role in PCB manufacturing. A copper clad board is common in the PCB industry. This is because it offers great features. It is an ideal option for high-frequency applications.
Copper clad laminates are widely used to design copper clad boards. These laminates soak in resin with some reinforcing material to make copper clad boards. Copper clad PCBs are available in computers, television, and other electronic devices.
The importance of copper clad is to enhance anti-jamming capability and minimize ground wire’s impedance. Copper clad also reduces the voltage drop of a circuit board. The copper clad boards feature glass fiber as a reinforcing material.
Copper PCB board is lightweight, strong, and durable. This board features electromagnetic shielding benefits. Several industries, including the military, incorporate this board in their devices.
Types of Material used for Copper Clad Boards
Manufacturers use different types of materials for copper clad PCBs manufacturing. We will discuss some of these materials here.
FR-4
This is one of the most common materials used in copper clad board manufacturing. FR-4 is an effective material with great features. It functions well and is cheaper than other materials. Over time, experts have studied FR-4. Therefore, it can help to manufacture various boards such as halogen PCB.
FR-4 features flammability of –UL-94VO. This material is ideal for high-end applications as it features a Dk of 1MHz -~4.7. The thermal conductivity of FR-4 is about 0.8 W/m/K. Also, it has got CTE of – ~55ppm/℃ before glass transition temperature. The CTE value is ~285ppm/℃ after glass transition temperature.
Copper foil
This is an electrolytic cathode material. Manufacturers deposit copper foil on a thin layer of metal foil on the base of a board. Copper foil can bond to an insulating layer. This helps to create a protective layer to shield the circuit board from corrosion. Copper foil features high conductivity of heat. Manufacturers apply copper foil on a PCB in electromagnetic shielding.
Prepreg
This is fiberglass pre-impregnated with resin. The resin must be dry enough, but not too hard. This will help it to flow and immerse during heating. Prepregs are like FR-4 materials that are reinforced by an adhesive layer. Manufacturers may have different requirements as regards the types and thickness of resin.
CEM-3
This means Composite Epoxy Materials Grade-3. CEM-3 is a fiberglass composite material with a mixture of woven glass fiber. It also contains non-woven glass and core raisin filling. CEM-3 features low mechanical endurance. It is a cost-effective alternative to FR-4. It also has a thermal conductivity of about 0.8w/m/K. The dielectric constant of CEM-3 is 1MHz-4.5~4.8.
Features of the Best Copper Clad PCB
You know the best copper clad PCB board through the feature it possesses. The following features are what make good-quality copper clad boards;
Exceptional chemical performance
It is important to note the chemical performance of a copper clad PCB. A copper clad board with great chemical performance is ideal for electronic devices. The chemical performance of this PCB must meet the stringent requirements for Tg. Also, it must meet the requirements for CTE on a Z-axis and chemical regents resistance.
Great Appearance
The appearance of a copper clad board matters a lot. There are issues that could happen due to unforeseen elements in the fabrication process. Issues like resin points, scratches, wrinkles, and more could occur. If a copper clad board has any of these issues, it will cause poor performance.
Exceptional Physical performance
The physical performance of a copper clad laminate includes peel strength. A copper clad must also feature great heat resistance and dimensional stability. These are some of the attributes that make up the best copper clad PCB.
Size
A copper clad PCB features a copper clad laminate as the base material. Therefore, this laminate must meet some size requirements as regards the intended end design. Manufacturers must consider all parameters. These include the diagonal deviation, length, and width. Meeting these requirements birth an effective copper clad PCB.
Good electrical performance
The best copper clad laminate features a good electrical performance. Manufacturers need to meet strict requirements like dissipation factor and volume resistance.
Why is Copper Used in PCB?
Copper is one of the most common materials used in PCB manufacturing. The most significant and popular benefit of copper is its high conductivity. Copper is a highly conductive material that can transmit signals easily. It doesn’t lose electricity while transmitting these signals.
PCB manufacturers don’t need to use tons of copper during manufacturing. A small amount of copper has a significant impact. An ounce of copper can cover a whole square foot of a circuit board substrate. Another benefit of copper is that it is widely available and inexpensive. It is a cheaper alternative to other materials.
Circuit boards need electricity to function well. The titular circuits in PCBs are crucial pathways that distribute electric charges from one place to another. These pathways must carry the charges efficiently. Although other materials can carry these electric charges, copper is conductive. Therefore, it is a standard option in the rigid flex PCB industry.
Copper is highly conductive because it features one valence electron. Such electrons can move from one atom to another without much resistance. Electrons are basic particles that carry electrical charges. Therefore, valence electrons transfer electrical signals. With all these features, copper is considered the ideal element for cladding PCBs.
Copper clad PCBs are more affordable when compared to other PCBs. Copper features almost 98% conductivity. Hence, PCB manufacturers use it to clad circuit boards. The large area of copper clad PCBs increases the shielding and current of the circuit.
Tips in Fabricating Copper Clad Boards
Copper cladding is a crucial aspect of PCB design. However, manufacturers need to pay attention during the fabrication of copper clad PCBs. Here are some tips for fabricating copper boards;
It is important to perform different treatments based on the positions. This is necessary when there are several grounds like AGND, SGND, and GND. Asides from this; it is advisable to hold the power connection.
- It is best to connect by 0 ohm resistor for the single connection of various grounds.
- Pay equal attention to grounding when you begin the layout. It is advisable to create a good layout instead of banking on vias to remove the ground pin.
- Avoid cladding copper on the extra layout area of multilayer boards.
- Do not allow sharp cornerson the circuit board. From an electromagnetic perspective, a corner on the board indicates that a transmitting antenna will impact the circuit later. Therefore, it is advisable to apply a rounding
- Ensure you ground the radiation metal of the voltage regulator to achieve the good grounding
Manufacturers should take note that good cladding on PCB enhances performance. Copper clad boards are ideal for use in several applications. These boards are commonly used in high-frequency applications.
Designing Copper PCB Board
There are software for designing copper PCB boards. Some designers create their prototypes in their lab. Doing this provides them an insight of possible quality problems in their PCBs. However, you will need to get PCB copper clads use for etching.
Altium designer is one of the best programs for designing your copper clad PCBs. This software features the tools needed to build your layout. Also, it includes features to help you design copper PCB boards. Copper clad boards are laminates you can use in a board stackup during the etching process.
Copper etching can be harmful if you don’t handle chemicals well. However, it is a simple way to create your own board without exporting a design to a fabricator. A designer may need to create a simple prototype by etching copper clad circuit boards. But, the designer needs to make a PCB layout with the use of professional design software.
If the layout is successful, you can convert to a CAD file and print it as a negative etching stencil. You need a good program to help you design these CAD files. Altium designer can help you achieve this. Copper clad PCBs feature some design requirements. However, they need to ensure the design can be etched using a ferric solution.
Copper PCB boards manually etched are more likely to feature larger traces. They also have larger pads and have no small drill holes. Cooper boards are either fabricated as one-layer or dual-layer boards. This is because there are no stacking and pressing procedures in these PCBs. You need to create copper clad boards with similar design tools as complex boards. In any circuit board layout, routing, component placement, and via design are important.
Classification of Copper Boards
There are different classifications of copper boards based on some standards. Copper clad boards are in many categories. Therefore, these boards are classified by;
Insulating structure and material
Copper boards are in different categories based on their insulation material and structure. Therefore, there are organic copper boards, metal base copper boards, and ceramic base copper boards.
Rigidity
Copper boards are in two main categories according to rigidity. The first one is the flex copper clad boards. The second one is the rigid copper boards. The flex copper boards are suitable for applications that require flexible boards.
Reinforcing material
Based on reinforcing material, copper boards are in three categories. They are paper base copper PCBs, compound copper PCBs, and glass fiber cloth base copper PCBs. Glass fiber products or paper are common reinforcing materials for PCB copper clad.
Insulation resin
The insulation resins in copper clad boards are epoxy, polyester, and phenolic resin. Therefore, copper clad PCBs are in three categories according to their insulation resin.
What is a Double Sided Copper Clad Board?
Copper Clad boards are available in single sided and double sided. A double sided copper clad PCB features two sided copper traces with a bottom and top layer. These boards feature conductive copper on the two sides of the circuit board.
Double sided copper clad boards are one of the most common PCBs. These boards allow manufacturers to design complex circuits. Double sided copper clad boards are ideal in higher technology applications. Vending machines, lighting systems, and more feature double sided copper clad boards.
Manufacturers prefer double sided copper boards because they use more complex circuitry. The greatest advantage of these boards is that there is an extra layer where you can add more components. This helps to increase the circuit’s density.
Frequently Asked Questions
Where are copper clad boards used?
Copper clad boards are ideal for use in several applications. You will find these boards in consumer electronics like computers, television, and radio. They are also widely used in applications that require high frequency. These boards are ideal for use in the telecommunication industry.
What are the standards for copper clad PCBs?
According to ASTM D1867, copper boards must meet peel strength at high temperatures. These boards must also feature lengthwise and crosswise flexural strength. Copper clad boards must also conform to tests for twist, warp, and blistering. Copper clad PCB manufacturers have to follow the IPC-4101C standard. The IPC-IM 650 is the standard test for copper clad boards.
Conclusion
PCBs provide mechanical support to components on electronic devices. These boards also offer electrical interconnections between components on the circuit. Copper clad boards are commonly used in the electronic industry. Copper is a conductive material that enables heat dissipation in PCB. An increasing number of electronic devices are featuring copper clad PCBs. There is no doubt these boards play a significant role in electronics production.
