The modern trend in electronics is to make everything smaller and more ergonomic. If you’ve paid close attention to companies like Meta, you must have wondered how they were able to fit functional electronics in their AI and AR glasses. Seems unreal. But the secret lies in the PCB design. With multilayer PCBs, engineers can fit hundreds of circuits in a tiny piece of real estate to power complex functions.
Multilayer PCB stackups with 4 and 6 inner layers
As these PCB types become more adopted, it is important to consider their advantages and disadvantages to determine if they are suitable for your project. Let’s do this analysis below.
Multilayer PCBs allow for higher circuit density, improved performance, and space-saving designs — perfect for complex electronics. But they come with higher manufacturing costs, longer lead times, and tougher repairability. Ideal for advanced applications, but not always the best fit for simple circuits.
What you’ll learn in this article:
You’ll learn the top advantages that make multilayer PCBs essential for modern tech. You’ll also explore the downsides like complexity and cost. Lastly, you’ll understand where multilayer PCBs make the most sense.
Excerpt of Advantages and Disadvantages of Multilayer PCBs
Multilayer PCBs have become the go-to in smartphones, aerospace systems, and medical devices — and for good reason. With multiple conductive layers stacked and insulated within one board, they support advanced routing, higher speed signals, and miniaturization of electronics. However, this complexity doesn’t come without tradeoffs. From cost and manufacturing difficulties to tricky repairs, multilayer PCBs need to be used wisely. The decision to go multilayer must balance performance demands with budget and scalability.
Pros and Cons of Multilayer PCBs
- Higher circuit density enables more functions in less space
- Improved signal integrity due to better power distribution and EMI shielding
- Compact design supports lightweight and portable electronics
- Increased design complexity requires advanced CAD tools and expertise
- Higher cost and lower reparability compared to single or double-layer PCBs
Advantages of Multilayer PCBs
Small Size
Instead of laying out the circuit across a large surface area, multilayer PCBs stack the circuits vertically, creating a thick but small PCB. Such boards easily fit in phones, smartwatches, smart glasses, wearables, and other miniaturized electronics.
Light Weight
Although they have the same circuit size as large PCBs, small multilayer PCBs utilize fewer materials during construction, making them lighter. As such, these boards are ideal for portable electronics.
High-Density Integration
The component density in single and double-layer PCBs is limited by the board’s surface area. But multilayer PCBs arrange the circuits in multiple layers, which enables them to pack many fine features and components on the two surface areas. Designers have to primarily focus on routing and signal integrity though, creating a challenge that we’ll look at later in the article.
High Durability
By having multiple layers, multilayer PCBs are thicker than their single and double-layer circuit boards. While this limits flexibility, the thickness makes the board stronger and more capable of withstanding external physical forces in its application area.
More Power
Besides creating miniaturized electronics, the other essence of making multilayer PCBs is to pack more power in a tiny space. The large circuit can accommodate more electronic components, which gives the complete assembly more capacity and speed than a similarly sized single or double-layer PCB.
Excellent Electrical Performance
To achieve a fully functional multilayer PCB, a lot of thought has to be put into the wiring layout, stacking design, signal interference avoidance, and EMR reduction. Therefore, the end product is PCB with superior electrical performance, with features like multiple shielding layers and reference planes to ensure signal integrity.
Strong Thermal Dissipation Performance
In addition to the superior electrical performance, thermal dissipation must be planned carefully during design to evacuate heat from the internal layers efficiently. Features like internal copper ground planes can help with this, while thermal vias transfer the heat between the internal layers to get it to the ground planes or outside.
Other features that can be used to enhance heat dissipation include heat sinks, pad reliefs, and using the core in metal-core multilayer PCBs to distribute and channel out the heat.
High Reliability
The complex nature of multilayer PCBs demands rigorous testing steps during manufacturing and assembly. These check the electrical properties, thermal dissipation, mechanical strength, stability, and resistance to environmental conditions, which results in a highly reliable PCB that will provide a long service life in its application area.
Disadvantages of Multilayer PCBs
High Manufacturing Cost
A multilayer PCB with copper gold ISA
Perhaps the biggest disadvantage of multilayer PCBs is their high production costs, particularly during manufacturing. Their fabrication process involves multiple lamination, electroplating, and drilling cycles, which are costly. This becomes even more challenging if the board is rigid-flex.
On top of that, the cost of required materials (high-performance adhesives and substrates) can add up.
Design Complexity
Before even getting into manufacturing, there is the design process, which has its own set of challenges. Things like impedance control, stackup design, thermal design, and track width/spacing make the process difficult. And once the design is complete and put into manufacturing, making changes is difficult because multiple factors must be considered.
Long Production Cycle
The complexities involved in multilayer PCB design and manufacturing lengthen their production time, meaning the time to market will be longer compared to single and double-sided circuit boards. This can affect product competitiveness in the market.
Maintenance or Repairs are Complex
Electronics can fail due to manufacturer or user errors, or even normal wear. If this happens, the board should be repairable. But maintaining multilayer PCBs isn’t as easy as handling single or double-layer circuit boards. For starters, faults are difficult to locate because they can be in the internal layers. And once detected, fixing them can be challenging because you’d have to get through several components, which will take time and require specialized skills.
Conclusion
As the world shifts towards the miniaturization of electronics, we cannot do without multilayer PCBs. So if you need such electronics, the best solution is to sort out the disadvantages listed above, which is only possible if you get a capable PCB contract manufacturer, such as WellPCB. WellPCB’s multilayer PCB manufacturing service is highly sought after in the industry because the company has the expertise, equipment, and experience to build these PCBs at reasonable costs and at relatively short turnaround times. The company also provides multilayer PCB component assembly services to round up the production process and send you complete prototypes or mass-produced boards for launch. Get in touch with WellPCB to learn more about their multilayer PCB production capabilities.
Multilayer PCBs offer high circuit density, better performance, and compact design. They are great for advanced electronics like smartphones and aerospace tech.
They are more expensive to manufacture, harder to repair, and require complex design tools and expertise — not ideal for simple or budget-sensitive projects.
They’re widely used in high-performance electronics like medical devices, military systems, laptops, and communication equipment due to their compact and powerful layout.
By placing power and ground planes between signal layers, multilayer PCBs reduce EMI and crosstalk, ensuring stable and clean signal transmission in complex systems.
