Download a free trial to find out which Altium software best suits your needs
Contact your local sales office to get started on improving your design environment
Download the latest in PCB design and EDA software
Complete Environment for Schematic + Layout
Entry Level, Professional PCB Design Tool
Community Based PCB Design Tool
Agile PCB Design For Teams
Connecting PCB Design to the Manufacturing Floor
Complete Solution for Library Management
Extensive, Easy-to-Use Component Database
Natural and Effortless Power Distribution Network Analysis
World-Renowned Technology for Embedded Systems Development
Learn best practices with instructional training available worldwide
Gain comprehensive knowledge without leaving your home or office
The easiest way to visualize your electronic designs online
Annual PCB Design Summit
Where Altium users and enthusiasts can interact with each other
Our blog about things that interest us and hopefully you too
Submit ideas and vote for new features you want in Altium tools
Help make the software better by submitting bugs and voting on what's important
A stream of events on AltiumLive you follow by participating in or subscribing to
Information about participating in our Beta program and getting early access to Altium tools
Explore the latest content from blog posts to social media and technical white papers gathered together for your convenience
Take a look at what download options are available to best suit your needs
Contact your local sales office to get started improving your design environment
The documentation area is where you can find extensive, versioned information about our software online, for free.
View the schedule and register for training events all around the world and online
Browse our vast library of free design content including components, templates and reference designs
Attend a live webinar online or get instant access to our on demand series of webinars
Get your questions answered with our variety of direct support and self-service options
Stay up to date with the latest technology and industry trends with our complete collection of technical white papers.
Quick and to-the-point video tutorials to get you started with Altium Designer
Altium is led by a team of highly passionate industry experts
Announcements to the ASX market from the preceding 3 years
Our customers can be found changing every industry; see how
PCBs are layers of copper foil and laminate. Industry standards for material selection are found in IPC-2221 and available in Altium Designer for inclusion in design documents.
TOPICS IN THIS SOLUTION
The most powerful, modern and easy-to-use PCB design tool for professional use.
Printed Circuit Boards (PCBs) are made by stacking layers of copper between layers of pre-impregnated (prepreg) epoxy/laminate. The most common prepreg in use today is FR4 for its flame-retardant and easy sourcing characteristics. It is rated to provide a high degree of electrical insulation in both dry and humid conditions while maintaining mechanical strength. FR4 is a grade of material and is typically made with a combination of materials composing a nonconductive glass-epoxy layer.
Materials other than glass-reinforced epoxy laminate are available although their cost is prohibitive for most manufacturing and design requirements. The Institute of Printed Circuit Boards, the industry standard providing certification for PCBs, offers guidelines for choosing materials in IPC-2221, the Generic Standard on Printed Circuit Board Design. The standard contains a wealth of information on base materials including prepregs and adhesives. Other material considerations for solder paste and plating are covered, in addition to markings and legends.
Employing qualities of PCB laminates for design features such as dielectric properties, creation of embedded passives, or thermal management is also possible. Electrical properties are typically controlled in the PCB by varying material width and thickness. Tables are available specifying parameters for all comparison of PCB materials, including FR4, within IPC-2221. Fabricators are also able to provide material properties of prepreg offerings for use as design features for your circuits.
Define layer materials and thicknesses
The industry primarily uses grade FR4 nonconductive material between layers of copper to build printed circuit boards. FR4 is a NEMA grade designation for glass-reinforced epoxy laminate material. The designation represents the ratio of fiber to resin and indicates characteristics such as flame retardant, dielectric constant, loss factor, tensile strength, shear strength, glass transition temperature, and z-axis expansion coefficient. FR4 is flame retardant making it suitable for safety requirements, and it is robust in varying temperature and humidity environments, increasing the quality of performance.
The laminates are placed between layers of copper and become substrates with dielectric properties relevant to the circuits assembled onto the boards. Designers specify substrate thickness to meet dielectric requirements for the circuits. IPC-2221 contains tables specifying dielectric constant for varying thickness of FR4 and other laminate materials possible for use in PCB substrate layers.
Another material consideration when designing PCBs is the thickness of copper plating. Typical designs use 1 oz copper for power and ground planes to accommodate multiple signal paths during circuit operation. With multiple currents passing through either the power and ground plane simultaneously during operation enough copper must be designed into the plane. Typically, power and ground planes are specified to 1 oz of copper. Signal planes are typically designed to ½ oz copper given one electrical signal traveling through them at any one time. For high-speed traces, more or less copper may be specified to meet impedance characteristics for the trace. Other material considerations include hole plating, solder paste, and solder mask.
Fabricators continue to discover materials better suited to high-speed signals. Materials can negatively affect signal integrity and nonwoven glass, and other, laminates are being found to reduce interference of the signal to maintain integrity. These materials are suitable for radar and microwave but the materials are more expensive to produce. Consulting with fabricators is a good plan for finding the sweet spot between signal integrity and design cost to manufacture.
View electrical and mechanical material layers
There are Presets within the tool that let you choose the number of layers. Up to 32 layers may be specified for electrical and mechanical characteristics. Established signal and plane layers and their location within the design are managed here. Mechanical layers with fabrication notes are available to view.
You may also use the views to analyze your electrical and mechanical layers for material needs to meet design use. Design for Manufacture includes consideration of common fabrication materials versus the need for signal integrity. Additional material characteristics to analyze against your design would be dielectric properties such as breakdown voltage and the substrates ability to prevent leakage currents.
Layers of a PCB are built with laminates to build the substrate and with copper to support signal propagation. Fabricators start with a core which is made with a substrate and copper foil. The core is composed of substrate with copper foil adhered to both planar sides of the substrate. Signal traces are etched from the copper using vector information contained in gerber files. To build more layers, additional cores are etched specific to the artwork and then adhered together with prepreg. Prepreg is typically the same material used as the substrate in the core. The same material is used for impedance matching characteristics to maintain design integrity. For multiple layer boards, several cores are etched with the design and laminated together with prepreg to produce the final layer stack.
The layers are heated and pressed together, causing the prepreg to form around the etched traces. This leaves no gaps within the material. Industry machines are controlled to ensure that the layers remain uniform. Without careful fabrication techniques, layers become uneven and opportunity for shorting increases.
Create your stack and specify dielectric constants and overlays
Each layer of your design may be specified for material and thickness with Altium’s Layer Stack Manager. Material properties such as dielectric, copper, and solder mask are detailed for eventual communication to your fabricator in the assembly documents. Properties such as thickness, clearance from plane edge to board edge, coverlay expansion, and component orientation on the outer layers is specified. Materials for solder and paste mask are detailed, along with drill files and plating needs.
Getting your designed stack documented for communication with fabrication houses occurs in Altium’s Layer Stack Manager. Layer Names, type of layer and its material designation, thickness, dielectric type and constant are all specified in the Layer Stack Manager. The information is available for publication to assembly drawings for communication with fabrication house. Altium Designer’s Draftsman tool provides information on copper and layer stack material dielectrics required for realizing the design.
Materials for solder paste and hole plating are communicated as well. Use of RoHS materials is becoming the norm as removal of lead and other toxic materials become mandatory worldwide. With lead-free solder and solder paste, PCB materials withstand greater temperatures during manufacture so any special instructions can be added here.
Assembly instructions and fabrication details are enumerated on the general purpose mechanical layers built into the layer stack. Special layers within the Layer Stack Manager are dedicated to specify silkscreen, solder and paste mask, drill information, keep-outs and connection layers. Each item in the Layer Stack Manager is accessible with a double-click followed by edification.
Communicating material specifications to fabricators happens with Altium’s Draftsman tool. Draftsman takes information the Layer Stack Manager and displays material properties explicitly on the assembly drawing. Fabricators use this information to make the printed circuit boards.
An important step in PCB design is specification of materials for communication to fabricators. Altium’s Layer Stack Manager is the tool that offers up to 80 layer templates to specify electrical, mechanical, special, or other layers necessary for fabricating a printed circuit board.