Have you ever wondered how PCBs make it easier for us to achieve what was once impossible in the electronics industry? Today, we’ll learn more about the amazing types of PCBs that aim to make our lives easier and more colourful. Printed circuit boards (PCBs) help us achieve the modern advancements we strive to make in today’s time.
Here, we will talk about the two types of PCBs: multilayer PCBs and prototype PCBs, such as their production process, their roles in the electronic industry, why they’re important, where they’re utilized, and how they help to shape our advanced electronic world.
Multilayer PCBs: Circuit boards with three or more copper layers
When we think of a PCB, the image of green, white, black or even blue circuit boards with copper traces may come to mind. While this classic image represents the appearance of printed circuit boards, and the colours are just the colour of solder masks, a complete PCB is much more complicated than this.
Back to the topic today, a multilayer PCB is a type of electronic board with three or more copper layers. Rather than only two layers, it has many copper layers, and the copper layers are separated by dielectric such as FR4 material. Depending upon how complex the electronic devices should be, these boards can be anywhere between three layers to one hundred layers and more! Everything relies upon what the electronics should do.
Multilayer PCBs
What Makes Multilayer PCBs Important
- High Density and Miniaturization: One of the critical benefits of multilayer PCBs is their capacity to pack a significant number of electronic parts and route them into a compact space. This thickness and miniaturization make them fundamental for the steadily contracting electronic gadgets we depend on every day, for example, cell phones and wearable devices.
- Improved Signal Integrity: In fast electronic frameworks, it is important to keep up with signal integrity. Multilayer PCBs succeed in such a manner by offering committed ground and power planes that act as shields, reducing electromagnetic interference (EMI) and crosstalk between signal traces. This guarantees the dependability and function of the final product.
- Complex Circuitry: From laptops to telecommunications and aerospace systems, complex electronic devices require multilayer PCBs. Their various layers give a designer of routing choices, empowering specialists to plan complicated hardware that meets the most requested functions.
- Less Size and Weight: Multilayer PCBs add to lessening the size and weight of electronic gadgets, a critical factor in convenient innovation. By stacking traces and vias in a multilayer structure, these PCBs work with the production of multifunctional and lightweight gadgets.
- Enhanced Reliability: The different layers in multilayer PCBs offer redundancy, reducing the risk of a single point of failure.
Manufacturing Complexity of Multilayer PCBs
Multilayer PCB’s advantages are obvious. However, producing them is not very easy. Production of multilayer PCBs is demanding and calls for detailed experience.
This being said, let us consider the manufacturing procedure for these PCBS.
- Step 1 – Inner layer Copper Etching: First, we need to etch out the inner layer copper traces. This is very similar to the production of a two-layer PCB. For example, we need to etch out the copper trace in layers 2 and 3 if we produce a 4-layer PCB.
- Step 2 – Layer Stacking: The inner layer is done at the beginning of the process. The second is to combine the inner layers and outer layer copper with prepreg. We can stack these layers according to the layers in the Gerber files. There should be a careful alignment for every layer of it to guarantee accurate connecting.
- Step 3 – Drilling and Plating: After lamination, the holes can then be drilled on the PCBs. This facilitates the location of different components between two or more layers. Copper plating is used to create electrical contacts among different layers through these holes.
- Step 4 – Outer Layer Copper Etching: After stacking the layers, the access copper in the outer layers is then removed in the next stage. Much precision and control must be applied in order not to etch or under-etch.
- Step 5 – Solder Mask Printing: A thin solder mask layer will be printed on the top and bottom of circuit boards to prevent pollution and oxidation to the copper trace. It has another function: to uncover the pads which need to be soldered with components. Green is the most commonly used colour, but white, red, black and blue are also not hard to see.
- Step 6 – Silkscreen Printing: We will print a layer of white marks (usually) on the PCB surface. The function is to help people know what components should be assembled at this place, which is very helpful in PCB assembly process.
- Step 7 – Surface Treatment: A thin layer of metal will be added to the pads from both the top and bottom layers. It is used to protect the pads from oxidation and damage. The commonly used surface finishes are HAL, ENIG, OSP, ENEPIG, immersion tin, immersion silver and hard gold plating.
- Step 8 – Testing and Inspection: Quality standards for multilayer PCBs must be carefully tested and inspected. At this last phase of production, any errors or flaws are discovered and corrected. We will do 100% open and short tests, AOI inspection and visual inspection.
Prototype PCBs
Prototype PCBs: The Precursor to Excellence
It bears repeating that although PCBs are the most complex type of electronic components, every success story always begins with the first step. To be honest, prototype PCB helps their engineers & developers to sail in the most dangerous sea—electronic development.
The Role of Prototype PCBs
Prototype PCBs play a pivotal role in the development process of electronic devices:
- Validation and Testing: One should always ascertain the functionality of a PCB before committing to a massive production. Following this, prototype PCB acts as a foundation for a thorough evaluation, identification of anomalies, and correction of any flaws.
- Design Refinement: Prototyping allows for further customizing a design by considering the feedback that comes out of testing in practice. This continues until the last PCB reaches the demanded level of quality and requirements.
- Cost Savings: Cost-saving measures can be undertaken if problems are identified during the prototype stage. The prototype makes expensive erroneous activity and redoing impossible in case of mass manufacturing.
- Risk Mitigation: It assists managers in minimizing risks that arise as a result of complex, sophisticated, or novel designs. Engineers will be able to test various sizes and functions of hardware and other combinations by providing virtual operating space for them.
Types of Prototype PCBs
Prototype PCBs come in various forms to suit different development needs:
- Single-Layer PCB Prototypes: They are quite simple and inexpensive for basic circuit testing and verification.
- Double-Layer PCB Prototypes: Designers opt for double-layer prototypes due to their greater complexity as it reflects the increased sophistication of technology used.
- Multilayer PCB Prototypes: Multilayer PCBs can be as many as 100 layers, which would be very expensive, so it is very important to produce a few pieces of prototypes first to avoid mistakes and big losses.
- Flex PCB Prototypes: Flex PCB, also called flexible PCB, is made of a special substrate which can be bent. The most commonly used material is polyimide and PET.
- HDI PCB Prototypes: HDI PCB is short for high density Interconnect PCB. It is a kind of multilayer PCB with complex blind and buried vias, and very tiny copper traces. It is obvious this kind of PCB is very expensive, and prototype production is a must.
- Quick Turnaround Prototypes: Rapid development and testing may be necessary for other projects. Prototype services with a quick turnaround time that assures fast manufacturing and distribution.
The Prototype PCB Development Process
Creating a prototype PCB involves several stages:
- Design and Layout: During this process, the engineers use specialized software to generate a PCB design about the components’ placement, routing connections, etc.
- Prototype Fabrication: Following this, the fabrication service develops the prototype based on the printed circuit board design. Typically, this entails etching, drilling, solder mask printing and surface treatment.
- Assembly and Component Placement: Once done, electronic parts are meticulously placed on and soldered onto the prototype PCB.
- Testing and Validation: The prototype is subjected to strict testing to ensure that it meets the set expectations. This includes a functional test and a signal integrity test.
- Iterative Refinement: Upon evaluation of test outcomes, and prototyping where needed for desired performance quality to be realized.
- Finalization: After the PCB prototype meets all requirements and specifications, a final PCB design is ready for mass production with valuable learnings from the prototyping process used to improve the quality of the product.
Conclusion: Turning Into Practice
Two essential pillars within current electronic design are multilayer PCBs and prototype PCBs. Multilayer PCBs stretch the limits of complexity and minimize size in such a way that electronic devices with high performance are created which cannot be dispensed nowadays in our life. In contrast, prototype PCBs act as a stepping stone to innovation by enabling engineers to validate and refine the design before mass production.
These two types of PCBs represent the unstoppable progress and incessant innovation that prevail in the realm of electronics where humans boast of advancements. These devices are that link of thought conversion from an idea to a tangible device that shapes our future.
