Multilayer Printed Circuit Board

Multilayer printed Circuit board is applicable in modern times as many electronics utilize it in their application. Multilayer printed circuit boards comprise two or more PCB layers or have at least three conductive layers within their insulating material.

This complex design has several applications in many consumer electronics today, such as smart TVs, computers, and smartphones. This article provides everything you need to know about Multilayer printed circuit boards.

What is a Multilayer printed circuit board?

Multilayer printed circuit board is a PCB with at least three conductive copper foil layers. They often take the shape of stacked double-sided PCBs on top of one another. The electrical connections between the layers are made possible through Vias.

Multilayer printed circuit boards are typically rigid, making it difficult for these stacked PCBs to be flexible. Depending on the customer's request, a Multilayer printed circuit board can stack up to 100 layers of PCBs.

Usually, Multilayer PCBs are often in even numbers of layers such as two (2), four (4), six (6), eight (8), ten (10), and so on. The reason is that printing odd number layers is not cost-effective and could cause warping in its entire circuitry. Also, most modern electronics utilize between four and eight layers of PCB in their design and application.

The need for Multilayer printed circuit board.

PCBs have played a pivotal role in the electronics industry for a long time. As time progresses, electronics become increasingly complex in their designs and applications. Processes or functions that single PCBs could perform without breaking a sweat became increasingly tasking with technological advancements and innovations.

Hence, many PCB manufacturers have to develop PCB stacking solutions to actively meet the requirement of these electronics by introducing Multilayer printed circuit boards. These PCBs stack enough power without taking up significant space in the electronics and can handle the tasks and needs of existing electronics.

Multilayer printed circuit boards brought incredible innovation to the modern world. With the recent adoption of the miniaturization of electronic products, multilayer PCBs play a pivotal role in its success. They also determine the electronic system's functional and thermal performance, ensuring they are smart, efficient, reliable, and robust in its applications.

Benefits of Multilayer printed circuit board.

Now that we have discussed the need for Multilayer printed circuit boards in electronics design and application let's consider its several benefits.

Compact Size

One prominent feature of Multilayer printed circuit boards is their small size. Because of their layered structure, they are small and can perform significantly better than single PCBs. Many consumer gadgets employ the compactness of multilayer PCBs in their applications, like wearables, smartphones, tablets, and laptops.

Increased Durability for long-term use

Multilayer printed circuit boards are naturally durable as they can withstand their weight. They can withstand internal pressure and temperature that were applied during their construction.

The protective and insulating materials used in Multilayer printed circuit board construction increases its Durability.

More powerful in application

multilayer printed circuit boards are high-density PCBs that stack multiple layers into a single PCB. This design makes these layers more electrically connective and allows components to interact speedily in a compact space.

Interestingly, old gadgets usually use four to eight layered PCBs, while modern devices use up to twelve.

Single Connection Point leading to lightweight design

While Multilayer printed circuit boards exist in layers, their design is to function as a single unit. Hence, they have one connection point making them effective in gadgets that require a small form factor in their application.

Disadvantages of Multilayer Printed Circuit Board.

While modern appliances attest to the benefits of Multilayer printed circuit board, it still has drawbacks, especially during its Manufacturing and designing process. Here are some disadvantages to utilizing Multilayer printed circuit board

Complex design process

Designing a single printed circuit board takes a few minutes to a few hours from software to design. Compared to Multilayer printed circuit boards, it takes several hours to design them. Also, multilayer PCBs must follow design rules strictly, or it could affect their overall performance. Stacking up PCB layers increases the number of active and passive components mounted on each board, adding complexity.

Higher cost of production

Since Multilayer printed circuit boards are complex by design, they are more expensive than single- or double-sided PCBs. The increasing amount of labor, advanced design, and costly assembly machines drive the price linearly.

Requires expertise in its production

Designing multilayer printed circuit boards requires expertise and experience in CAD tools and understanding design rules involving Multilayer printed circuit boards. Also, domain expertise is essential when designing multilayer PCBs.

With more complexity in the Multilayer PCBs' design, it leads to multiple PCB experts designing and assembling it to function optimally.

Applications of Multilayer Printed Circuit Board

Despite certain drawbacks, Multilayer printed circuit boards have become a vital part of electronic products in this modern world. Any gadget you interact with today has elements of stacked PCBs in them.

Many Industries today benefit from Multilayer printed circuit boards. Take a look at the defense, Automotive, and Aerospace industries.

Military and Defense

Military operations require high-functioning and high-speed circuits. As such, multilayer PCBs are excellent in the military field. This industry is shifting towards compact engineering designs. Multilayer printed circuit boards are ideal due to their powerful yet small form factor.

Automotive

The automotive industry has seen massive shifts as self-driving cars and electric vehicles are available in the market. Several automotive manufacturers employ high-tech electronics to control everything from headlight switches to navigation systems. As such, they need high-functioning multilayer PCBs that are heat-resistant and durable to perform several operations in an automobile.

Aerospace industry

Aerospace requires high-precision devices and equipment. From the computers used in the control tower to those in the cockpit, the Multilayer printed circuit board must be reliable and withstand atmospheric changes. This industry deals with the lives of several personnel and customers, so the use of high-quality and precise Multilayer printed circuit boards is essential.

Others

While we cannot mention all existing gadgets, let's consider a few typical applications of Multilayer printed circuit boards.

Mobile Phones

Home Automation systems

Laptops and computers

Broadcasting systems

Radar systems

Alarm systems

GPS technology

Signal transmission systems

Medical devices include heart rate monitors, blood pressure monitors, Blood sugar monitoring, and ECG devices.

The manufacturing process of Multilayer Printed Circuit Board

As this guide explained, Multilayer printed circuit boards require unique expertise and design rule, as there are many connections, overlaps, and copper traces. Yet, these are the steps involved in the multilayer PCB manufacturing process:

Software design

The first step towards the Multilayer printed circuit board manufacturing process is designing the circuit board layout. Users can employ any PCB designing software, such as Eagle, Proteus Altium, and KiCAD.

Production of inner layer core

After the design process is complete, making the inner layer core is the next step. Also, laminating the desired thickness with copper foil and dry film resists.

Lamination

The next step is laminating the inner layer core, prepreg, and copper foil sheets. The sheets are then stacked on each other with their vias used as alignment.

Application of heat and pressure

The next step is to apply heat and pressure using a heated hydraulic press. Also, vacuuming is vital in this step to ensure no trapped air between the layers.

Combining

After the curing process, resins from the prepreg join the core, foil, and sheet to form a Multilayer printed circuit board.

PCB Vias in a Multilayer Printed Circuit Board

A via refers to an electric connection between different layers on the Multilayer printed circuit board. They are often seen as small PCB holes that pass through multiple layers.

Depending on the design process, multilayer PCBs may require vias to pass through all layers or just the outermost layers. Hence, PCB manufacturers make use of three kinds of vias in PCB design and manufacturing:

• Standard via
• Blind via and
• Buried via

Standard Via

These vias are also referred to as through-hole vias. They are visible from the top end to the bottom end of the printed circuit board. The via hole is covered with copper to form an electrical connection between the layers of the circuit board.

Standard vias have larger dimensions than other types of vias. They are also easier to make since they offer no restrictions in their drilling process.

Blind Via

These vias are drilled from the top layer to the inner layer without being visible on the other side of the Multilayer printed circuit board. They require greater precision in their drilling process to ascertain when to stop to achieve the desired depth in the stacked PCBs.

Blind Vias are applicable in increasing the connections between the top and inner layers of the printed circuit board.

Buried Via

This kind of Vias is not visible on either side of the printed circuit board. The internal drilling and plating must be completed before the board's outer layer is implemented on a Multilayer printed circuit board.

Buried vias add to manufacturing costs, requiring precision in the design process.

Conclusion

There you have it! The complete guide to Multilayer printed circuit board. This guide provided the importance of multilayer PCBs in modern electronics while showcasing its strength and weakness in their design process and application.

It is imperative to check with your PCB manufacturer the layer count they can design and assemble to ensure your PCB needs are met. Suppose you are searching for the next best PCB manufacturer to handle standard multilayer PCBs. In that case, NextPCB is available to provide for your PCB needs.

With several PCB services on its sleeve, this excellent PCB manufacturer ensures your circuit board designs become real and get to your doorstep quickly. Make it a conscious effort to check their product line and be assured of the best PCB service that is second to none.