Copper Wear Shorts Can be Avoided with Strong CAD Tools
With manufacturability at the heart of the designing process, always.
While the phrase “PCB design” seems to emphasize design, it actually covers all aspects of printed circuit board manufacturing. Without the proper attention to design for manufacturability (DFM), the entire design process would take much longer and would encounter more problems. Designing for Manufacturability pushes design teams to take a much longer view of the design process and to consider the board from the perspective of fabricators. Gaining this perspective allows design teams to understand that problems occurring early in the design process can become larger—and even unmanageable—in the production process.
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Altium Designer prioritizes the long view of PCB design through a unified design environment that keeps design for manufacturability in focus through all stages of the design process. This focus becomes particularly important as the design transitions from the schematic editing stage of a project to the PCB layout stage. As design teams use Altium Designer, they can utilize Design Rule Checks to set constraints on the layout and active routing to precisely manage routing widths and spacing. In addition, the teams can effectively manage multi-layer designs and ensure that the design meets or surpasses the requirements set by a fabricator for high production yields.
Copper splinters can become a particularly bothersome by-product of the PCB manufacturing process. While chemical etching removes copper material from the board to create the traces, via pads, and planes established during PCB layout, the process of dissolving unwanted copper sometimes does not fully remove the copper. Two different--but related—problems may occur.
The process can allow a residue of long, sliver-like debris that separate from the board without dissolving. After the debris falls into the chemical bath, the pieces of copper float and then land on another board before fully dissolving. In some instances, the undissolved copper exposes copper plating normally covered by a solder mask and sets the stage for corrosion. Or….the debris partially detaches from the copper of the original board, flips out-of-control, and creates a short circuit across adjacent traces. With either type of copper splinter scenario, an ill-advised PCB layout can cause multiple, non-repeating problems that become almost possible to systematically troubleshoot.
Repairing Multilayer Mistakes in Circuits
The copper splinters—or copper wear shorts—often occur in areas of the PCB where trace and pad clearances intersect. When we consider the increasing use of high-density, multilayer PCB designs that rely on large numbers of vias and crowded traces to pass signals between layers, the probability of copper splinters becomes greater. Copper remains in these areas as clearances between traces and pads become extremely small. As a result, you need to establish design rules and electrical rules that address trace widths and clearances.
- Learn about multilayer designs
- Learn about multilayer design tolerances for manufacturing
- Learn about distinctions between multi-board and multilayer designs
Altium Designer protects against design flaws that reduce clearances through design rules that describe every aspect of your design. As you move your design from concept to schematic and to PCB layout, the design rules establish instructions for the PCB Editor. Because the design rules define routing widths, clearances, routing via styles, and plane connections, the correct application of the design rules also protects fabricators from problems such as copper splints. Altium Designer uses the online Design Rule Checker (DRC) to monitor the design rules and to generate error messages if a rules violation occurs.
Altium Designer applies a hierarchical system as it applies design rules to specific objects. Because you can establish multiple rules of the same type to cover a design object within the same scope, the hierarchical system works through the highest through the lowest priority rules and uses the first rule that has a scope that matches the checked objects. With Altium’s approach to design rules and design rule checking, your design can rely on a group of rules with different requirements.
Design Rules and Constraints Editor for Concise Circuit Development
Width and Clearance rules define the amount of packing that can occur for your routing. Along with using design rules, you can also use the Electrical Clearance Constraint to define the clearance between electrical objects belonging to different nets. Defining the width and clearance for the routing establishes a balance between easier board fabrication and easier routing. Boards with wide traces and larger clearance become easier to fabricate while the opposite becomes easier to route. You can enter a value into Minimum Clearance field to automatically apply a value to all the fields in a grid region.
When using the PCB Editor, you can also define the PCB area available for component placement and routing. For example, you can use the Board Shape function to match the shape defined by a set of objects on one of the mechanical layers of the PCB or you can assign a layer sub-stack to a specific region of the board shape.
- Learn about design rules in Altium Designer
- Learn about design rules to fanout a large BGA
- Learn about using rules-driven design for a high frequency board
Layer stack configuration is vital for manufacturing
Another Altium Designer tool found within PCB Editor—interactive routing—allows you to gain the precision needed for your PCB layout and to prevent copper splinters. Interactive routing allows you to define a route path from a pad to a current cursor location through the use of algorithms that follow electrical and routing rule definitions.
The possibility for copper splinters becomes minimized through the use of the Routing Width Design rule and Track Width Mode setting within interactive routing. Both tools establish constraints for the trace widths. In turn, the Routing Conflict Resolution mode allows the router to respond to existing objects and apply a conflict resolution strategy.
Finding hot wire potential or thermal expansion within an electric field can be immensely helpful while in the prototyping or design phases of a circuit board. Knowing power demands and power irregularities can keep your printed circuit in check before resistance, flow, and electrical current comes into play. Ensure that you are safe with the current flow for your conductor and aluminum wiring and trust Altium Designer to work through potential power difficulties.
Detangle Routing Webs with Sophisticated Autorouters
Interactive routing follows the design rule checks and electric rules that support DFM and assist with eliminating copper splinters. In addition to setting the trace width and distances, you can determine the corner style that eliminates sharp corners. You can also use interactive routing to precisely place components.
With the dynamically optimized connection tool found in the PCB Editor, you can establish shorter, untangled connection lines. The PCB Editor also maximizes the free space between components by placing the similar-sized surface mount components opposite one another on double-sided boards and by placing components on pads established to a regular grid.
- Learn about maximizing prouction yield
- Learn about seamless PCB documentation
- Learn about getting started with Design for Manufacturing (DFM) guidelines
PCBs need strong routers to work through their difficulties
The unified design environment found within Altium Designer supports the production of a PCB design from schematic through layout and to documentation. The PCB design software generates manufacturing outputs, the BOM, Gerber files, and other types of documentation. With this information, your PCB design team can work with any fabricator and any manufacturer.