PCB Stackup Design: Technologies and Key Considerations for High-Performance Circuits
The term “stackup” refers to the process of arranging the layers of copper and insulation that comprise a printed circuit board (PCB) before finalizing the design. With the rise of modern technologies, compact electronics have become essential, making PCB layer stacking vital in electronics. To achieve a compact design for electronic products, designers often opt for multilayer PCBs with a three-dimensional appearance.
Multilayer hardware design provides several benefits, such as improving the PCB board’s ability to efficiently distribute energy, reducing electromagnetic interference, minimizing crosstalk, and supporting high-speed signal transmission. Modern PCB stackup design also plays a critical role in maintaining signal integrity, power integrity, and thermal stability in high-speed and high-density applications.
Stackup technologies
With advancements in precision manufacturing, engineers can choose from multiple PCB stackup technologies based on design requirements. A well-defined stackup depends on several critical factors:
Key Factors for Stackup SelectionKey Factors for Stackup Selection
- Number of layers: Determines routing capability and design complexity
- Operating frequency: Higher frequencies demand better signal integrity control
- Signal & Power Integrity requirements: Ensures stable performance and minimal noise
- EMI/EMC compliance: Reduces electromagnetic interference and emissions
- Via technology selection: Includes plated through vias, blind/buried vias, and microvias (HDI)
Common Stackup TechnologiesCommon Stackup Technologies
Standard Stackup (Plated Through Hole – PTH)1. Standard Stackup (Plated Through Hole – PTH)
- Connects multiple copper layers using plated through vias
- Simple, reliable, and easy to design and manufacture
- Offers a higher fabrication yield compared to advanced stackups
- Cost-effective for low-to-medium complexity boards
- Limitation: Not suitable for high-density or compact designs with fine-pitch ICs
HDI (High-Density Interconnect) Stackup2. HDI (High-Density Interconnect) Stackup
- Designed for compact and high-density electronic devices like smartphones and tablets
- Uses sequential lamination and multilayer structures
- Incorporates laser-drilled microvias for tighter routing
- Enables component placement on both sides of the PCB
Provides:
- Better electrical performance
- Reduced layer count
- Improved routing efficiency for high-speed signals
Via Technologies Used in StackupsVia Technologies Used in Stackups
Blind Vias
- Connect the outer layer to the inner layers
- Useful for reducing via stubs and improving signal integrity
- Helps in optimizing routing space in dense designs
Buried Vias
- Connect inner layers only (not visible externally)
- Ideal for complex multilayer PCBs requiring internal routing optimization
Considerations & Limitations
Increasing blind/buried vias:
- Adds lamination cycles
- Increases manufacturing cost
- Leads to longer fabrication time
- May impact plating thickness on outer layers
Rules for Proper PCB Stackup Design
Like any other design or product manufacturing, designers need to follow some rules to produce the highest quality products. As you already know, electronics go through several processes which involve different components before producing the final product. Therefore, designers must ensure they identify and follow proven design PCB stack-up best practices. For PCB stack-up design, some rules should be followed to get the best results.
- The first and foremost rule is the use of ground planes. They are the best choice due to their ability to route signals in strip lines. In addition, it also plays a vital role in reducing ground noise. Ground noise gets significantly reduced because of the reduced ground impedance.
- When it comes to high-speed signals, they must be routed to an intermediate layer that sits between different levels. In this manner, the ground plane acts as a shield and suppresses the radiation emanating from the orbit at maximum speed.
- Signal layers must be close to the plane.
- Mass planes and power should be carefully connected.
- It is necessary to ensure that the configuration is symmetrical.
- Signal impedance requirements are met.
- It is necessary to consider the thickness of each signal layer.
- Moreover, it is also essential to consider the properties of the desired material. Also, pay special attention to such materials’ thermal, electrical, chemical and mechanical properties.
The Impact of Poor PCB Design on Electronic Performance
Great PCB hardware design means a great deal. Businesses must have quality products and results. As you already know, circuits today operate at extremely high operating speeds, making it extremely necessary to optimize your PCB design. Comprehensive PCB design needs to make this craft an art. The reason for this is that you can have a good design or a bad design. However, a poorly designed product can seriously degrade or affect the performance of an electronic product. Some of the effects of poor PCB design include poor signal transmission, low-quality power output, and reduced durability of electronics. To avoid such occurrences, it is recommended to ensure that the PCB is of high-quality design.
Optimizing Your PCB Design: A Guide to Stackup Selection
Conclusion
PCB stack-up design is essential for both designers and electronic engineers. The ability to come up with high-quality electronics requires several considerations. Without a high-quality PCB design, the product’s quality and performance can be significantly affected. Therefore, designers must ensure the right stackup construction and PCB materials are selected to obtain a high-quality product. A high-quality PCB stack-up goes a long way in getting the highest quality PCB yield and productivity.
Stackups designed for High-speed designs are costlier than those used for non-high-speed applications. Compensating the stackup quality for cost can result in poor signal integrity, which makes the PCB unsuitable for high-speed applications.
Usually, designers use standard and HDI stack-ups while designing PCB stack-ups since both provide unique features and benefits that appeal to designers and engineers. Businesses can select the most suitable one based on the design and performance they expect from the PCB.
The Tessolve PCB team has rich experience in designing complex Stackups. Be it high-layer count (60+), multi-laminate, or HDI stackups, Tessolve can support designing a manufacturable, cost-efficient stackup that still meets all the Electrical requirements.
Tessolve works closely with Fabrication shops to create the right stackup at the design stage and run DFM checks in-house, which allows us to achieve an incredibly high first-pass acceptance rate and eliminates delays getting designs onto the production floor.
For better assistance from our experienced engineers, email us today at sales@tessolve.com
Tessolve PCB team has rich experience in designing complex Stackups. Be it high layer count (60+), Multi-laminate or HDI stackups, Tessolve can support designing a manufacturable, cost-efficient stackup that still meets all the Electrical requirements.
Tessolve works closely with Fabrication shops to create the right stackup at the design stage and run DFM checks in-house which allows us to achieve an incredibly high first-pass acceptance rate and eliminates delays getting designs onto the production floor.
For better assistance from our experienced engineers, email us today sales@tessolve.com
Frequently Asked Questions
1. What is PCB stackup design?
PCB stackup design refers to arranging copper and insulating layers in a circuit board to ensure proper signal flow, power distribution, and overall electrical performance.
2. Why is PCB stackup design important?
PCB stackup design is important because it directly affects signal integrity, power integrity, EMI control, and overall reliability, especially in high-speed and high-density electronic applications.
3. How do you build a PCB stackup in design software?
To build a PCB stackup, define layer count, assign materials, set thickness, configure impedance, and validate using tools like Altium or Cadence Design Systems.
4. What factors should be considered when designing a PCB stackup?
Key factors include layer count, signal speed, impedance control, material properties, EMI requirements, and via types to ensure optimal performance and manufacturability.
5. What is the difference between standard and HDI PCB stackups?
Standard stackups use plated through vias and are simpler, while HDI stackups use microvias and enable higher density, better performance, and compact designs.
