In multilayer PCB (Printed Circuit Board) design, precision is not something to strive for, it’s necessary! With higher circuit density and ever-smaller components, even one minor error may cause functionality problems or scrap delays in manufacturing. For these reasons, PCB design services stress the importance of Design Rule Checks (DRC) as a part of the workflow.
When it comes to multilayer boards, the DRC does allow for checks to be implemented to verify spacing, trace widths, via structures and layer-to-layer connections are within design and manufacturing constraints.
Multilayer boards are less simple than single-layer boards. The addition of multiple copper planes, overlapping signal layers and high-speed routing makes it harder for the user to detect violations visually. Automated DRC helps engineers catch potential violations early in the process and create boards that are manufacturable, meet the needs of performance and can be put into production in volume.
What is a Design Rule Check?
A Design Rule Check (DRC) is a checked step in an electronic design automation (EDA) tool in order to verify your layouts against recognized rules or constraints that have been established prior to design.
Rules may include:
- Minimum spacing between traces
- Trace width with respect to current
- Drill and via diameter
- Clearance of copper to edge of board
- Alignment of layer stack
Rules may go even further such as impedance control in multilayer designs and ensuring separation between power and ground planes and consideration of crosstalk. The intention is to try to ensure that the design can not only be electrically functional but also reliable enough for manufacturers to produce the printed circuit board (PCB).
Why DRC is Vital for Multilayer Boards
- Managing Layer Complexity
Multilayer PCBs can be anywhere from four layers to well over twenty layers, depending on the specific application. Without strict rule enforcement, routing errors or misaligned layers could leave the board inoperable. The DRC will check every layer methodically to confirm how many of the layer alignments, connectivity and will verify manufacturability.
- Ensuring Electrical Integrity
Signal integrity is imperative when designing high speed multilayers. The DRC will check that impedance controlled traces, differential pairs and spacing requirements, will minimize crosstalk or unwanted coupling. This will prevent downstream failures at product testing.
- Mitigating Manufacturing Risks
Multilayer manufacture consists of sophisticated drilling, lamination and plating operations. infractions, such as annular ring size and via dimensions violations can lead to increased scrap. automated design rule checking (DRC) identifies errors early in the design phase to eliminate costly re-design and manufacturing wetness.
- Compliance to Industry Standards
Several industries (such as automotive, aerospace and medical devices) are required to comply with regulatory standards DRC is used to ensure multilayer designs are compliant with standards while maintaining traceability and reducing non-compliance risks.
Common Rule Checks in Multilayer PCB Design
- Clearance Rules: Check to ensure that there is enough spacing between conductive elements to avoid shorts or arcing.
- Trace Width Rules: Check to ensure that amperage capacity will be met without generating excess heat.
- Via and Drill Rules: Check to validate plated vias for hole diameter and pad size, including annular rings.
- Edge Clearance Rules: Keep copper from being placed too close to the edge of PCB.
- Impedance Control Rules: Control impedance is maintained during high-speed signal transmissions.
All of the rules above are enforced automatically by design software giving the engineer peace of mind that the multilayer PCB will function as it was intended to after it is manufactured.
Best Practices for Running DRC in Multilayer Projects
- Adjust Rules for Each Project: Not every board has the same requirements. Adjust rules by application, current flow or on the manufacturing process abilities.
- Run Incremental DRC Checks: Don’t wait to run DRC checks at the completion of the design review, run a DRC on the layout as you go!
- Talk with Manufacturer: Send the design rules to your fabrication partner to ensure the layout rules align with their ability to manufacture.
- Integrate Compliance Early: Think of compliance, reports for conflict mineral compliance to start with and work along with electrical rules in order to ensure both compliance with regulations and environmental needs.
Sunstream’s Expertise in DRC and Multilayer Design
Design Rule Checks should not only be considered a backstop for difficult multilayer PCB development. Design Rule Checks are at the core of successful multilayer design, allowing engineers to manage complexity, guarantee manufacturability and comply with all requirements before committing costly rework.
In designing and producing multilayer PCB successfully, Sunstream applies extensive domain knowledge and where required, a structured PCB workflow to achieve accurate, reliable and compliant multilayer PCB.
We support our clients in reducing design errors, shortening product development time while achieving reliability in performance in the product.
By integrating the design best practices from the technical world with regulatory and compliance requirements for multilayer PCB, Sunstream enables organizations to take their multilayer PCB project from the concept to production with confidence while minimizing risk and maximizing efficiencies.
Sunstream delivers specialized PCB design services in which we have helped our clients move towards a DRC strategy where multilayers PCB meet performance requirements while meeting regulatory requirements, reducing costly iterations and moving towards sustainable products.
+1.585.935.7123
+91-804-148-6861