In the past, PCBs were relatively simple. However, new advancements in technology have made it possible to create complex boards that can do far more than their counterparts of the past. Multilayer PCBs are helpful when creating more advanced electronics.

The Multilayer PCB

A PCB is considered multilayer when it has three or more layers with conductive copper foil. The layers are circuit boards with two sides that have been laminated and then glued together. They also include insulation between the layers to help protect the boards from heat. The electronic connections that take place between the layers happen through vias. These might be blind vias, buried vias, or with plating through holes in the board. This allows for there to be more connections and can make for complex printed circuit boards.

The multilayer PCBs became essential when the need for more sophisticated electronics rose. The standard PCBs were not capable of handling the needs of the new electronics because there would often be issues with stray capacitance, crosstalk, and noise. The multilayer PCB can help to deal with those issues. The number of layers that are used in these boards will vary. Typically, applications will require between four and eight layers, but it depends on several factors.

Why Choose Multilayer PCBs?

These types of PCBs offer a range of benefits. One of the most common reasons for using the multilayer PCB is the size. Because of the layered design, it means that the PCB will be smaller than other printed circuit boards but still have the same level of functionality. Most people today want their electronics to be smaller, while still being powerful. The multilayer PCB allows for this. These types of boards also happen to weigh less, which helps to reduce the overall weight of the gadgets in which they are used. However, the size is certainly not the only benefit.

Typically, these boards will also be high-quality and very reliable. A lot of work goes into the design of the boards to ensure they will work. When combined with quality materials and construction, they can last. They are known for being durable, and a big part of this is the insulation layers that are between the board layers.

The connections on these boards are closer together than they are on standard PCBs. This means that they tend to be more connective and more powerful. They will have a greater capacity, as well as improved speed. The multilayer PCBs also have just a single connection point. This is helpful in the design of the final product in which they will be used. It will mean that the product only needs to have a single connection point. This allows for more design freedom for those gadgets.

These are some of the biggest benefits of multilayer PCBs. If you aren’t already considering using them for your next design, it might be time that you thought about it.

Common Real-World Applications for Multilayer PCBs

These types of boards are often considered the go-to type of printed circuit board to use because of the advantages mentioned above. They are found in many different types of consumer electronics, for example. They are used with smartphones, tablets, microwaves, smartwatches, computers, and much more.

Multilayer PCBs are also used in the telecommunications industry. They are often used for satellites, signal transmission, GPS, and towers. They are used in many industrial control systems, as well as in the automotive industry. Many vehicles today are heavily reliant on computer technology. These boards allow for complex electronics in a smaller space.

The boards are becoming common within medical industry electronics, as well. They are used for a range of different types of equipment that helps to diagnose and treat patients. Multilayer PCBs can be found in heart monitors, CAT scan equipment, and a host of other devices. The functionality, durability, small size and low weight help to make them a good solution for many military and aerospace applications, too.

As you can see, multilayer PCBs are the solution for just about any type of industry today. Above are just some of the different ways that they can be used. There are not any major disadvantages to using these types of boards. Even though there may be increased production time, this can be mitigated by finding a reputable company with a fast turnaround time.

Choosing the Right Manufacturing Company for Multilayer PCBs

When you are looking for a manufacturing company that can create the boards for you, it is important to ensure that they can handle all of the needed layers. Some of the companies available may not be capable of creating the number of layers needed for the boards you are creating. At Advanced Circuits, we have standard specs that can create 0 to 10 layers, and our custom specs can provide 0 to 40 layers. This should be more than enough for any multilayer PCB you might be designing.

When you choose Advanced Circuits, you will have more than just quality materials and the ability to create a large number of layers. You will find that our customer service helps to ensure that customers are happy from start to finish. We have a free software package that will make it easy for designers to create the boards they need and to test them to see whether they work before going ahead with a prototype.

We offer a fast turnaround time, great prices, and reliability. Additionally, you only have to order as many PCBs as you need, since we do not have a minimum. Get in touch today to learn more about how we can help.

Whether you’re an expert engineer or an at-home inventor, you’ve likely designed PCBs that fail due to a short circuit or burnt-out component. PCB designs are incredibly intricate, and you’re not alone in your trial and error. Circumvent some of these hard lessons by checking out these tips to optimize your PCB layout for a better performing PCB.

Research                                                                                                                   

Before you begin drawing up the plans for your next PCB, pause for a moment to consider why. Is your goal to improve an existing circuit board? Are you dreaming of an entirely innovative concept? Whichever your reason, make sure you know your end goal and research whether there are existing circuit board templates that you can use. This pre-work will save you a ton of time and keep you from reinventing the wheel if a solution already exists. You’ll also avoid repeating the mishaps of others when designing your PCB layout.

Create a Blueprint

Once you’re set on the outcome you’re hoping to achieve, it’s time to put your ideas into something tangible. Start with a hand-drawn sketch to map out your circuit board. This will allow you to see the flow and catch any errors before adding in the complication of technology. You can also have colleagues or other PCB hobbyists review your circuit board layout ideas for input before creating your virtual design.

Use a (Free) PCB Software

With your blueprint in hand, you’re ready to start designing the layout of your PCB. The best way to create a PCB layout is by using free PCB design software, like Advanced Circuit’s PCB Artist. PCB design software, like PCB Artist, will give you access to a components library with over 500,000 parts. It’s incredibly easy to search for a previously used component, add it, and rearrange as needed for your PCB layout. Never pay money to use PCB design software, as there are so many excellent free choices on the market.

This digital blueprint that you create using a PCB software is called a schematic. In your schematic, you’ll place your components, connectors, connections, and power sources. Eventually, this will become your PCB design that a manufacturer will use to create your PCB.

Most free PCB design software also comes with a design rule check so you can be confident that your PCB layout works and can be produced by the manufacturer of your choice.

Placement

The placement of your components during the schematics stage is incredibly critical to the viability of your PCB. Typically, you want to start by placing your most essential elements first, and then go from there with any flairs or add-ons. Keep in mind that you don’t want to overcrowd your PCB. Placing components and active elements too close together can result in high temperatures. Overheating your PCB can cause components to burn and, ultimately, lead to your PCB failing.

You’ll also want to check with the manufacturer, and during the design, rule check to see if there are placement restrictions. In general, you want to leave at least 100 mils of space between any component and the edge of your PCB. You also want to evenly space out your components and organize so that like-components are oriented the same direction, as possible.

Routing

As you plan and design your PCB’s layout, you’ll want to consider the different routing options and specifications. On a finished PCB, the routing is the copper traces that run along the green board and indicate the flow of electricity between the components. The general rule of thumb is to make the route distance between elements as short and direct as possible. You also want to make sure that you make your traces wide enough to handle the high temperatures in an electrical circuit. When in doubt about your PCB overheating, you can always add in via, or holes, to channel electricity to the other side of the PCB.

Layers

Thanks to advances in our scientific understanding of electricity and circuits, we can now easily manufacture PCBs with multiple layers. The more layers you have on a PCB layout, the more complex your circuit will be. Extra layers allow you to add in more components and tends to have higher connectivity.

Multilayer PCBs appear in more sophisticated electrical devices, but if you find your PCB layout is becoming overcrowded, this could be an excellent way to problem-solve. Multilayer PCB designs do come with higher costs, but Advanced Circuits offers excellent deals on two and four-layer PCB fabrication.

PCB Manufacturer

You’ve put in the hard work and effort to design your PCB, so make sure you select a manufacturer that can bring your plan to life. Different PCB manufacturers use different fabrication processes and use varying qualities of components. It would be a shame to have an incredible PCB layout, only to receive a low-quality product with a lousy soldering job or faulty components. Choosing a manufacturer that uses surface mounting technology is your best bet for a PCB that precisely represents your PCB layout. This fabrication method is mostly automated and reduces the risk of human error when creating your physical PCB.

Create a Prototype

Even if you’re 100% confident in your PCB, it’s always a good idea to order a prototype. Even experts know that you’ll likely want to make tweaks to your PCB design once you see how your prototype performs in its given application. After testing out your prototype, you can go back to the drawing board and update your PCB layout for optimal output.

Advanced Circuits Can Help

Advanced Circuits is the third largest PCB manufacturer in the U.S. Their company has you covered from beginning to end in your PCB layout process. You can utilize their free PCB design software and file check to ensure your layout is bug-free and ready to go. Advanced Circuits has an incredibly accurate fabrication process that will ensure your PCB is delivered precisely as you designed it.

After all, prototyping means designing something new, having the unit made, addressing flaws or design issues, and only then sending it into production. There is always the risk that a design flaw might be overlooked, and working with subcontractors can actually increase such concerns. All of these factors are why so many people will avoid the entire process and stick with a less than desirable solution. Settling for a stock or standardized design, however, is not a forward-thinking approach.

The good news is that there is no such thing as one size fits all circuit board design. Advanced Circuits, a top industry manufacturer, offers an array of resources capable of empowering firms with even limited budgets to upgrade, customize and enjoy flexibility. Of course, it helps to have a bit more clarity on just what is available generally before delving into the options in custom printed circuit board design.

The General Options in PCB Design

A simple or basic list of the options for PCB design include:

• Single Layer
• Double Layer
• Multi-Layer
• Rigid
• Flexible
• Flex-Rigid
• High-frequency
• Aluminum-Backed
• Full Spec
• LDI
• Oversized
• Heavy copper
• and more

Clearly, this means an array of production capabilities has to exist and come in at the right price and quality points to meet such a diversity of potential needs or designs. Advanced Circuits can supply almost any type of production capability and facilitate premium circuit board design that goes along with it.

Optimal Circuit Board Design from Advanced Circuits

In addition to there being such a diversity of PCB types, there will be many design needs. For example, printed circuit board design may involve only a single layer, or it might be two-sided, but the complexity of modern electronics may necessitate up to 28 layers incorporated into a design, and each layer will require synchronous interaction. This means there is always room for error in circuit board design, and the option for multiple sets of eyes and various levels of expertise may prove remarkably beneficial and cost effective.

Because of that, Advanced Circuits has created a system of tools, resources and services that are all meant to facilitate optimal circuit board design. The resources and services include:

• Expert advice – In addition to classic customer support, our team includes access to CAM engineers 24-hours each day. Customers are able to phone in design and engineering questions and have them answered by a professional engineer.
• Expert Reviews – CAM engineers also conduct a thorough review of each design as it is about to enter into the production process. This is a final check and guarantees that there are no issues that might lead to a negative outcome.
• Full and free design support – In addition to expert engineers, Advanced Circuits offers industry best software meant to enable superior design. PCB Layout Software – PCB Artist features a library of more than 500k tools and components that can be built into designs of up to 28 layers. It can control auto router functions, multi-page schematics, and more. It is offered in an unrestricted format, meaning it comes at no cost but allows top-of-the-line design options.

After that, clients are able to use the FreeDFM program, which requires an export to Gerber file format and upload to the Advanced Circuits website. Once that fast and easy process has been completed, the client can enjoy a full evaluation of the PCB design. A report is emailed to the provided contact and it explains which flaws were discovered, remedied and what were targeted as potential showstoppers, but left in place.

As any professional knows, PCB design is the key factor in the whole process. A single error makes a prototype a failure or an entire batch of PCBs useless. It could lead to enormous wastes of time and resources. Yet, the entirety of the process does not begin and end with design. There are other factors that impact whether or not printed circuit board design is as successful or effective as it could be.

A lot of it has to do with the approach the producer takes to the process. Advanced Circuits ensures that its clients experience a process that empowers their success, from the design phase to assembly. This means that we:

• Keep it in house – Our enormous production facilities are Advanced Circuits’ way of proving commitment to the entire process. We are able to work with design files and a team of engineers that ensure files are complete and appropriate to the client’s goals. However, we also handle fabrication and assembly on the premises, too. While so many modern manufacturers are “no touch,” we are most distinctly hands-on and manage every aspect of a project.
• Comprehensive website – The ease with which clients can get the tools needed and then use them effectively is only one part of our service. We also provide instant quotes, unique client pages where previous orders and simple reorders are possible, stencils, file uploading, order tracking, and “through software” orders. Design something using the free PCB Artist software, and order it once it has cleared the CAM or free evaluation services. This also gives clients a discount on any standard spec orders.
• Tooling fees – Many manufacturers impose a tooling fee on standard spec orders, but clients can count on a fee-free process with Advanced Circuits. Even if a custom spec orders is re-ordered, the tooling fees are cancelled out.
• No minimum orders – Budgets are protected by Advanced Circuits’ no minimum order requirements, and whether it is a single board with a single day of turnaround time or a huge order, the quantity is in the hands of the clients.

Advanced Circuits Removes the Challenges in the PCB Production Process

The PCB design and production process is full of potential challenges and issues. Advanced Circuits clients receive their specific designs without breaking the budget, slowing production times or wasting resources. Whether clients need one PCB, small batches or larger orders, Advanced Circuits can produce quality printed circuit boards to client requirements.

To get an instant PCB quote and learn more about our quick turn capabilities, review our standard and custom spec PCB page.

Available Laminate Materials for Multilayer PCB Designs

We offer many laminate material options for your multilayer PCB requirements including the following:

FR4 for Multilayer PCB

• Standard FR-4: Up to 40 Layers
• Isola FR406: Up to 40 Layers

Halogen Free Laminates for Multilayer PCB Designs

• Ventec VT-441, VT-447: Up to 40 Layers
  Isola Terragreen: Up to 40 Layers

RoHS Compliant Materials for Multilayer PCB

•  ITEQ IT-180A: Up to 30 Layers
•  ISOLA 185HR: Up to 30 Layers
•  ISOLA 370HR: Up to 40 Layers
• FR408HR: Up to 40 Layers
• ISOLA I-Terra MT (RF/MW): Up to 40 Layers
•  Nelco BT-N5000: Up to 30 Layers
•  Nelco 4000-29: Up to 40 Layers
•  Nelco 4000-13 & 13SI: Up to 40 Layers
•  Nelco 4000-13EP & EPSI: Up to 40 Layers
•  Polyimide: Up to 40 Layers
•  Cyanate Ester: Up to 20 Layers

RF Materials for Multilayer PCB Designs

• Rogers 3000 Series (FR4 w/ RO3000 Caps): Up to 20 Layers
• Rogers 4003C & 4350B: Up to 20 Layers
• Rogers 5870/5880: Up to 8 Layers
• Isola IS680: Up to 40 Layers
• I-Terra RF MT: Up to 40 Layers
• Isola Astra MT77: Up to 40 Layers
• Rogers 6000 Series: Up to 4 Layers
• Rogers Diclad 880: Up to 20 Layers
• Rogers AD300A: Up to 20 Layers
• Rogers CuClad 280: Up to 20 Layers
• Rogers CTLE: Up to 20 Layers
• Isola I-Speed: Up to 40 Layers
• Arlon Genclad 280: Up to 10 Layers
• Arlon LX250: Up to 10 Layers
• Arlon GYN 2.17 DK: Up to 10 Layers

Advanced HDI & Signal Integrity Laminates

• Rohacell: Up to 12 Layers
• Isola Tachyon 100G: Up to 40 Layers
• Isola I-Terra MT 40: Up to 40 Layers

For more information about our multilayer PCB capabilities and available materials, please click here to contact your regional sales representative.

Expanded Capabilities Include Multilayer PCBs Up to 40 Layers

Advanced Circuits is able to meet the demand for the increased layer count of conventional circuit boards.  Multilayer PCB designs allow the engineer to create more powerful boards while at the same time shrink the overall size of the PCB.  To meet the demand for higher layer counts and more advanced PCB technologies, Advanced Circuits has invested heavily in strategic acquisitions and in state-of-the-art equipment which has allowed the company to offer the medical, aerospace and defense, industrial, and many other industries advanced PCB capabilities to meet their needs.  Learn more 〉

Prepreg Thickness Chart for Multilayer PCB Lamination

Prepreg is the material used in the multilayer PCB lamination process – a woven glass cloth with epoxy resin.

The chart below provides the thickness for a single ply (sheet) of each style of Pre-Preg after processing. These are grouped by the weight and type of the internal conductor layer (typical signal and plane layers) that they will be adjacent to (columns A-F).  Those that are adjacent to the top and bottom copper layers will use the column designated for these (column G) regardless of the layer type.  All plies that are not directly against a conductor layer (use for situations with more than 2 plies in an opening) will use the additional plies values (column H).  These values are based on a minimum of 2 plies of pre-preg per opening between foil and cores or between cores.

This thickness guide is provided as a guide only. The actual thickness will be affected by the copper distribution within the design as well as within the production panels. Learn more 〉

Other Advanced Capabilities

• Multilayer RF Designs Up to 8 Layers
• Heavy Copper Up to 20 oz.
• Oversized Boards Up to 37″ x 120″
• Laser Direct Imaging (LDI)
• Laser Drilled Microvias (HDI)
• Stacked Microvias
• Cavity Boards
• Via-in-Pad
• Air Pockets Between Layers
• Blind & Buried Vias
• Buried Chip Resistors
• .00275″ Trace/Space
• Down to .3mm Pitch
• Laminate options for high temp., low loss and lead-free materials

See full list of Advanced Circuits PCB Capabilities.

Advanced Manufacturing Capabilities for Multilayer PCBs

There is a growing demand for more advanced printed circuit boards including multilayer PCBs and a growing need for smaller and lighter boards for many applications; from smartphones to medical devices and military equipment.  Advanced Circuits™ has made significant capital investments in the latest state-of-the-art equipment in its three U.S. based manufacturing facilities to offer advanced capabilities that include: oversized boards, heavy copper (up to 20 oz.), multilayer boards (up to 40 layers), laser drilled microvias, via-in-pad, microwave & RF boards, and much more.

Benefits of Multilayer PCBs

There are many benefits to using multilayer PCBs that design engineers can use to their advantage:

• Reduced circuit board space/weight
• Increased functionality
• High capacity/speed in a smaller footprint
• Higher assembly density
• connectors required for multiple PCBs reduced or eliminated

Advanced Circuit’s™ has many resources and the industry’s largest support team to help you meet your project requirements.  Click on the quick-links below for more information about our multilayer PCB manufacturing services:

• Full Capability Sheet [PDF]
• Pre-Preg Thickness Chart
• Controlled Impedance/Dialectic

Due to the physical attributes of these PCBs, size for a particular circuit or application may result in the need for large boards, or even the use of multiple boards. This is where the advent of technology and manufacturing techniques that permits fabrication of multilayer boards has been a major leap forward for application in electronic products.

Multilayer PCB Advantages

Utilization of multilayer printed circuit boards presents board design engineers and product developers with many strategic advantages:

Space requirements – creating printed circuit board designs with multiple layers means a considerable savings of real estate within the products that take advantage of the technology. Considering that adding layers generates only a slight increase in thickness of the resulting board (depending on the number of layers), the benefits over larger single or double-sided boards can be considerable. This is critical for modern electronic devices.

Weight – just as with space benefits, combining layers of components into a single multi-layer card can provide circuit functionality with a fraction of the weight over prior technologies. Think of the advantages when introduced for use in personal electronics, laptop computers, and flat-screen televisions.

Reliability – construction of multilayer board contributes to a high level of reliability and consistent performance.

There are Downsides to Multilayer PCBs

As critical as multilayer boards are in enabling the development of high-performance, compact electronic devices such as smartphones, military equipment, aerospace instrumentation, etc., there are trade-offs to be considered in their development and use:

• Cost – this is the primary consideration. With the specialized equipment required to manufacture multilayer PCBs, manufacturers must pass that cost to the customers, making the PCBs more expensive than traditional boards. Fortunately, as demand has increased and technology has evolved, this gap has narrowed considerably.
• Design tools – creating detailed technical designs for fabricators means that design engineers and layout technicians must transition to sophisticated software to aid in the design and manufacturing processes. This requires training and a learning curve for designers.
• Replacements – due to the structure and complexity of multilayer PCBs, repair of a failed board can be extremely cumbersome, if even possible. In most cases, a failed board results in the need to replace it, rather than attempt repair.

Fabrication Considerations for Multilayer PCBs

Fabrication of multilayer boards is not available from all PCB manufacturers. With the increasing percentage of boards designed with multilayer requirements, the number of producers is expanding. Although the process is relatively straightforward, specialized equipment and attention to detail is required. Training in the techniques is also required for efficient production as quality improves with experience.

Manufacturing processes include construction of layers of conductive material such as copper foil, core material, and prepreg layers, sandwiched together with heat and high pressure applied to laminate the layers together. Heat serves to melt and cure the prepreg materials, and the pressure removes air pockets that could impact board integrity.

These processes require specialized equipment and a significant commitment to operator training, not to mention the financial consideration. This explains why some fabricators have been slower to enter the multilayer manufacturing market than others.

Technology that Supports Design of Multilayer PCBs

A significant development that enables the creation and integration of multilayer boards into so many industries and products is the creation of extremely sophisticated software tools that are available to design engineers, layout specialists, and fabricators.

PCB design software facilitates computer aided design (CAD) that empowers circuit designers to increase efficiency, spot errors or problem areas quickly, and generate files for fabricators that are less likely to be problematic for the manufacturer. Even the design files can be analyzed for missing or incorrect content, avoiding traditional back-and-forth communications when manufacturing questions or issues arise.

Design for Manufacturing (DFM) applications aid both designers and fabricators through analysis functions that validate manufacturability of the resulting design. Without a DFM tool, PCB designs can made it to a fabricator to find the PCB will be either impractical, costly, or even impossible to build as designed.

Computer Aided Manufacturing (CAM) software is used by the manufacturer to validate and automate the actual fabrication processes.

Combined, these sophisticated tools make multilayer PCB design and manufacturing more efficient, streamlining the process from end-to-end. The result is more reliable, less costly multilayer boards, with improved project timelines.

Smartphones and computers are perfect applications for multilayer PCBs with their need for compactness and light weight, yet sophisticated functionality.

From a technical standpoint, there are numerous advantages to the use of multilayer designs, over and above saving space and weight:

• By incorporating multiple layers in a single PCB, boards can increase functionality.
• Manufacturing processes for multilayer boards result in high-quality, reliable end products.
• Multilayer boards by their innate electrical properties provide high capacity and high speed in a smaller footprint.
• Higher density of assembly
• Connectors required for multiple separate PCBs are reduced or eliminated, simplifying construction and further reducing weight.
• Multilayer PCBs can be manufactured in both rigid and flexible construction. Be advised though, that the more layers incorporated in a flex PCB, the less flexible it becomes.

Downsides of Multilayer PCBs

Every technology has pros and cons, and multilayer PCBs are not immune from negative attributes:

• Cost – one of the primary negatives in designing and implementing multilayer PCBs is the cost. As specialized processes are involved in the manufacturing of these boards, there is a considerable investment required for fabricators to offer these services. This makes the cost of multilayer boards higher than a traditional single or double-sided board.
• Service availability – not all PCB manufacturers have made the commitment to manufacturing these complex boards, limiting the resource options available to PCB designers.
• Compactness of multilayer boards generates design concerns for such issues as crosstalk and impedance problems.
• With increased functionality comes the need for more extensive testing of a single PCB. Manufacturing cycles may also be longer, due to the very complexity of the manufacturing process.
• Repairing a multilayer PCB can be extremely difficult, and may even be unfeasible or impossible. This makes failure of a multilayer board costly, since it may need to be totally replaced.
• Interconnection between layers is critical for board function, making design and fabrication of microvias and overall density critical.

Processes for Manufacturing Multilayer PCBs

Due to the sheer demand for multilayer PCBs for use in technology devices, healthcare equipment, military use, and even such consumer products as smart televisions and home monitoring equipment, most competitive manufacturers have positioned themselves to respond to the need for these boards.  There remains a mix of capabilities among fabricators related to volume production capabilities, and the number of PCB layers that can be produced.

Manufacturing of multilayer PCBs involves a process of combining alternating layers of prepreg and core materials into a single unit, utilizing heat and high pressure to ensure uniform encapsulation of conductors, elimination of air between layers, and proper curing of adhesives that bind the layers together.

Due to the multiple layers of material, execution of drill holes among layers must be carefully observed and registered. It’s important for successful manufacturing of multilayer PCBs that engineers incorporate symmetrical layout across layers, to help avoid twisting or bow in the materials when heat and pressure are applied.

When sourcing a fabricator for multilayer PCBs, it is critically important to acquire the manufacture’s capabilities and standard tolerances for these complex boards, and utilize design for manufacturing (DFM) techniques to accommodate those standards. This goes a long way toward building confidence that the result will meet all functional, reliability, and performance expectations.