Best 8 layer PCB Partner for Your Project

Full range of PCB materials in stock
Monthly capacity: 50, 000 square meter
All processes in-house.

Why Choose PadPCB

When you send us the gerber file, our professional engineer will evalulate your design per layer and offer detailed quotation in short time.

The max capacity of our factory is about 50,000 square meter. It means that we can ensure the short turnout time for your project.

For each order, our sales will follow up all the manufacturing process and communicate with customer.

Our 8 Layer PCB Customers

FAQs about 8 Layer PCB

1. What is 8 Layer PCB?

8 layer printed circuit boards (PCBs) are high-performance, multilayer components. They comprise three parts: ground planes, power planes, and signal layers. These are firmly packed to ensure complex designs, provide space for routing, minimize crosstalk between signal layers, and so on.

A high-quality PCB stack up offers enough design flexibility without compromising size. It can be placed even into microelectronics to enhance the working speed of devices. 8 layer PCBs are optimal for advanced and high-cost electronics.

2. What is the typical 8 Layer PCB Stackup?

Stack up is the composition of layers, i.e., the arrangement of insulating and conductive layers. It is considered a crucial aspect of multiboards functioning as layer distribution should ensure a balanced structure.

Layers are not distinct sheets of material. They are sides of cores and prepregs:

Core is one or more prepregs laminated together with press and heat and coated with copper on each side.
Prepreg is composite material “pre-impregnated” with resin left uncured.

And here is the typical arrangement of cores/copper foils/prepregs on a 8 layer stack up:

As you can see, normally, we have three cores coated with copper, four prepregs, and external copper plating. There are thicknesses shown as well for your consideration. To be honest, thickness is the only aspect that changes since there is no other arrangement but this in 8 layer PCBs.

3. Advantages of 8 Layers PCB Stackups

Here is the list of notable ones:

Reduce vulnerability. External forces frequently lead to signal noises that deteriorate the performance of electronics. But 8 layer stack ups are way more sustainable than other options.

Reduce radiation. There is specific electromagnetic interference radiation, conceived, for example, during the continuous transmission of high-speed signals. The 8 layer stack up limits this negative effect.

Increase signal integrity. You definitely want impeccable operation from your devices, which is tightly connected to the integrity of the signal produced by a PCB. The inclusion of multiple ground and power planes serves as a shield for signal layers, hence improving their performance.

Cost-effectiveness. Having a 8 layer PCB as your option is a cost-effective decision. They require less maintenance, offer superior performance, and are long-lasting and durable. Even if they require higher investments, you will achieve a greater return per dollar spent.
Enhance functionality. 8 layer PCBs naturally improve the functionality of devices they are placed in. For example, they are more energy-efficient, ensure high signal speed, and are more reliable.

4. Guideline for 8 layer PCB stackups

There are some templates for 8 layer PCBs, but it is nearly one-tenth of what comprises a good board. We gathered some tips, advice, and core considerations to comprise this guideline. Meeting it will advance you in fabricating a high-performance 8 layer board.

Buried/blind/micro vias. These elements make the usage of PCBs space more rational. They optimize designs and help to achieve better performance in such dense stack ups as 8 layer PCBs. The use of micro vials is restricted by the choice of a substrate (for example, ceramic PCBs can employ the benefits from micro vias). But, consider buried and blind vias instead/together with plating through-hole vias.

Return current path. While designing a PCb, make sure that return paths, i.e., current paths/connections between independent circuits, are short and do not intersect with other elements. This will eliminate the probability of malfunctioning.

Ground planes alignment. When ground planes are split, it results in discontinuity of impedance. Besides, it is highly preferable that components on external layers have low impedance. To fix discontinuity and ensure the latter, ensure that you connect ground planes with each other using vias, regardless of the stack up template.

Core materials. We detailed what the core actually is above. But what’s more important, it is the substrate from which it is produced. Rogers, FR-4, ceramics, or any other materials must be chosen with careful consideration of your PCB’s finish purpose.

Bow and twist. The bow is simply the deviation from a board’s flatness, while the twist is the diagonal deformation meaning that one of the angles is not in the plane with the other three angles. Both result in even copper distribution, so you should ensure their prevention. We produce our PCBs in a symmetrical way to minimize the probability of bow and twist occurring.

Stackup measling. It is the issue when planes are stuck to each other with not enough insulation/resin in between them. We use silicone pads and epoxy plates while arranging a stack up to prevent measling from occurring. It also helps to maintain a board’s uniform thickness.

Interlayer offset. It is a problem when layers are moved and do not present a uniform stack up. It can be minimized by using the rivet dowels method in the process of fabrication.

5. Applications of 8 layer PCB

8 layer boards are widely used in the production of advanced and high-quality electronics. It is mostly because they rarely start malfunctioning. Here’s a brief overview of the types of electronics and industries for which we commonly fabricate 8 layer PCBs:

Medical industry. It includes advanced laboratory and surgery equipment. Microscopes, ultrasonic water baths, gas chromatographs, robotic stations, and many more.

Automobile industry. These are mostlyAirbag and LED light control systems, FM radio, automated locking systems, indicator lights, air conditioning control, and many more.

Manufacturing industry. In this category, 8 layer PCBs serve as components for industrial electronics like CNC equipment units, automated and robotic manufacturing lines, control panels, light and air conditioning control systems, and many more.

Chemical processing industry. Here 8 layer PCBs are presented with components for control panels, robotic systems, controllers of evaporators, dryers, heat exchangers, and so on.

Aviation industry. 8 layer PCBs that were constructed using Rogers and ceramic substrates can serve inside optical systems. Alternatively, they can be presented in engine control systems, power suppliers, radars, health monitoring sensors, and many more.

6. What is the thickness for 8 layer PCB

You can have 1 mm. 1.6 mm, 2.0 mm, 2.4 mm, and even 3 mm thick PCB, depending on your needs. You have been shown 8 layer PCB stackup in the section above. and here is the large-sized stack up:

Thicknesses of prepregs and cores can vary significantly, and normally you can produce any size. However, you should consider sticking to everyday standards because manufacturers keep them in mind as well while producing electronics. Offering PCBs with size deviations will instantly lead to lower demand.

Another point that impacts a 8 layer PCB’s thickness is copper plating/copper foil. It is often that you apply liquid copper and spread it evenly onto surfaces. So, it is more convenient to calculate it in oz rather than in mm. You may vary copper thickness as well, but there is no point in using anything but standard measures.

We can produce 8 layer PCBs as per all available standards. We are also open to fabricating customs stack ups as per your requirements.

7. What’s the cost for 8 layer PCB?

For an 8 layer PCB, it can be somewhere between $10 and $50 per board on average. However, the price may still vary significantly depending on the following factors:

Substrate material. Normally, manufacturers purchase some popular substrates such as FR4 or Rogers to ground PCB production on them. So, 100% of the market cost of substrates is included in the final cost.

Without deepening much in details, here are the considerations for choosing materials: thermal reliability, temperature reliability, heat transfer, signal performance, and mechanical properties.

PCB size. Stack ups are fairly rigid structures, and standard thicknesses are well-determined. It is also true for their dimensions. The typical sizes are: 18 X 24″ or (457 x 610mm), 18 X 21″ or (457 x 533mm), and 21 X 24″, or (533 x 610mm). The need for manufacturing large PCBs results in consuming a vast amount of materials and, respectively, in higher costs. Besides, the more space is available, the more components can be placed there.

Finish method. When you produce a costly 8 layer PCB, you naturally want it to be long-lasting. That’s why you need to apply a PCB finish. Your options here are HASL, LFHASL, OSP, IMM Ag, IMM Sn, ENIG, ENEPIG, and Elec Au. Hot air solder leveling is the cheapest option, while immersion gold is the most expensive one.

Hole sizes and their quantities. It is a simple factor, which is all about the tooling for producing holes – drill bits. In case you requested specific or microscopic holes, a manufacturer will have to use custom and special tooling and higher revolutions per minute. Production of complex holes is also more time-consuming. And, of course, requesting more holes than standard drill sets can produce will result in higher costs per board as well.

Minimum trace and space. In some cases, trace-carrying capacity, i.e., how much current they can transfer without overheating, is insufficient. It is so because of inadequate trace width. To compensate for this problem, manufacturers will have to add extra soldering or enlarge traces themselves.

Aspect ratio. It is another consideration related to drilling. Aspect ratio is the board thickness to the diameter of a drilled via. The larger this value, the more difficult it is for a manufacturer to fulfill the requirement for several reasons. It will need more expensive additives, advanced equipment, and custom tooling, perhaps.

Unique specifications. The obvious point is the need to follow your custom requirement, i.e., anything which is our os standard specifications. Examples are contoured edges, side-plating, and solder mask clearance. Having any illness results in the instant rise of cost as well.

8. 6 layer vs 8 layer PCB: What's the difference?

Probably you have heard that 6 and 8 layer PCBs are nearly the same. It is so because of a rule that simpler layout = performance, while on the opposite, more layers = more space for extra components. We sometimes have to explain the difference, so here are the key considerations:

Cost. In most cases, 6 layer PCB is cheaper to produce. However, an extra-complicated 6 layer PCB can be even more expensive than a normal, everyday 8 layer PCB.

Turnaround time. The situation is exactly the same as with the cost factor.

Scope of applications. The 8 layer PCB suits microelectronics a bit less for an obvious reason. 6 layer PCBs are used for different electronics more frequently. However, 8 layer PCBs have greater potential overall.

Performance. Having the same components and fulfilling the same function, 6 layer PCB will always perform faster. However, it can never achieve the same degree of performance as an 8 layer PCB can offer in the matter of versatility and a number of supported functions.

Design freedom. Having less space naturally restricts the design freedom, so 8 layer PCB is the absolute winner here.

In essence, 6 layer PCB is a better choice if you need to produce less advanced electronics. However, if you cannot effectively pack all the routing and components into 6 layers only, always go for 8 layer PCB.

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