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
You’ve just finished the electrical layout of your board and now you are working through the final steps to prepare for manufacturing. What steps do you need to take to get your board ready for production? Aside from generating deliverables like Gerber files, a bill of materials, drill files, silkscreen, and assembly instructions, you’ll need to define the solder mask on the surface layers of your PCB. This important production planning step is much easier when you use the right PCB design software with a full suite of design tools in a single program.
TOPICS IN THIS SOLUTION
The only unified PCB design package with a complete set of PCB design and layout tools for rigid, flex, and rigid-flex boards.
Once your layout is finished, you might be tempted to think that the last step in the design process has been completed and you can start planning for manufacturing and assembly. While this is technically true, there is on last design step that is critical for proper fabrication and assembly of your board. This step requires defining solder mask throughout your board. The goal is to provide sufficient protection to traces and ensure that solder only bonds to specific areas of exposed copper in your board.
There are other benefits to using solder mask that include preventing corrosion, bridging, and tombstoning during wave soldering. With the right design software, you’ll be able to define the important areas of your board that require solder mask and verify your coverage using native 3D design tools. Altium Designer is the only PCB design package that includes these features and many other tools that are built to help you move to manufacturing successfully.
In short, solder mask (also called solder resist) is an epoxy or photoimageable polymer layer that protects copper on the surface layer of the PCB. This layer covers exposed traces on the surface of the board, preventing oxidation and providing an extra protective barrier against mechanical damage.
Solder mask provides another benefit to your board; it helps prevent unintended connections from forming during assembly when components are soldered onto pads and holes. A solder bridge forms when two pads on a board or two leads on an IC package are unintentionally soldered together, which typically happens due to the use of too much solder paste during assembly. Defining the right solder mask opening size and thickness helps ensure that solder remains on a conductive pad during wave soldering. This also helps prevent tombstoning of components on the surface layer.
Solder mask was created primarily to facilitate wave soldering during in mass assembly. Proper use of solder mask is critical for ensuring proper wave soldering and unintended solder bridges during assembly of rigid circuit boards. As modern boards require higher trace density routing and component placement, PCB solder mask is something of a requirement rather than an option in most boards.
With flex ribbons in rigid-flex PCBs, or with fully flexible PCBs, you’ll need to decide whether to use flexible polyimide coverlay or flexible solder mask to protect critical traces on polyimide substrate. The answer to this important question really depends on whether you intend to solder components directly to the flex ribbon and the level of flexibility required on the finished PCB.
3D view of a PCB with blue solder solder in Altium Designer
The process of applying solder mask to the surface layer of a PCB includes several steps. First, the surface layer must be cleaned and degreased, and the copper surface is roughend mechanically or chemically. A solder mask layer is then applied as an epoxy-based coating or a polymer coating. More complex boards with finer features will use a liquid photoimageable polymer that is hardened using a photolithography mask. If you are working with a solid or liquid photoimageable polymer, your manufacturer will need to take your design files and construct a photolithography mask that contains the exposed conductors.
The final step after applying and exposing a solder mask involves removing excess material and curing the mask with a UV lamp or in a tunnel over. This process fully hardens the solder resist so that it will adhere to the board and roughened copper conductors in your PCB. Each component pad will then be left exposed through the solder mask opening and the board will be ready for PCB assembly.
Just like all other aspects of printed circuit design, there are industry standards that define design and manufacturing practices for solder mask. The IPC-SM-840D standards define solder mask requirements for a printed circuit board intended for use in certain industries or applications.
Silkscreen printing is another important aspect of preparing for assembly and will be placed after the solder mask has been placed and cured. Clearance and printing requirements on silkscreen on a the surface layer of a circuit board are specified in the IPC standards. A lot number and a unique manufacturer’s mark will need to be placed on the board using silkscreen in order to provide traceability in the event of a recall. Make sure to allocate space on your circuit board for this information and clearly specify this in your design.
Preparing Gerber files and assembly drawings in Altium Designer
The design tools in Altium Designer are built on a single rules-driven design engine that allows you to define solder mask clearances around pads and tolerances throughout your board. You'll usually want a two mil border around each feature to compensate for tolerances in the solder mask. You'll need to define clearances on other features in your board like pads and vias to ensure the solder mask can prevent solder bridges from forming.
When preparing your printed circuit board for manufacturing, the solder mask should be defined in its own layer in your Gerber files. The solder mask color is just one of many important points that will determine the type of solder mask that can be used on your board. It is best to check with your manufacturer regarding their capabilities and available materials when selecting a solder mask color, thickness, and other manufacturing tolerances while designing your board.
Once you’ve laid out your board and defined your solder mask openings, pad clearances, and thickness, it’s time to prepare your deliverables for your manufacturer. These deliverables include Gerber files, bills of materials, sourcing information, drill files, and other assembly instructions. These tasks are much easier when you work with design software that integrates these tools into a unified design environment.
Working in an integrated environment means that your design, verification, data management, and production planning tools have access to the same set of design data within a single program. You won’t have to export design data between programs, and each tool will be accessible within a single interface. Instead of resigning yourself to an outdated workflow, you design and prepare for manufacturing with maximum productivity when you use Altium Designer.
Solder mask is one of those all-important design steps that designers must complete prior to sending a board off for manufacturing. Your design tools should simplify the process prior to moving on to manufacturing. Altium Designer does more than just offer tools for solder mask design. The rigid-flex PCB design tools, PCB editor, schematic editor, documentation features, and circuit board analysis tools are integrated in a single environment.
Integrated design features are built to work together and have set the standard for productivity in the PCB design industry. If you need helpful design tips and resources, Altium gives you access to webinars and podcasts, the AltiumLive forum, and a thorough knowledge base with design examples. You’ll be able to design printed circuit boards for any application.
When you work with Altium Designer, you won’t have to sacrifice productivity by switching between multiple programs just to complete essential design tasks. Instead of using outdated command line-based design software or multiple programs to design your solder mask, try working with the industries best design features in a unified environment. The integrated design tools in Altium Designer are built to work together and help you maximize your productivity.