Cadence Paper: Automating Inter-Layer In-Design Checks in Rigid-Flex PCBs

Estimated reading time: 10 minutes

New In-Design Inter-Layer Checks Prevent Frustrating Iterations

For today’s flex and rigid-flex designs, PCB designers need to be able to perform comprehensive in-design interlayer checks of the non-conducive layers in rigid-flex PCBs, shortening the design cycle by minimizing ECAD/MCAD iterations and lowering overall end-product costs. Errors should be flagged as soon as they are created, following a correct-by-construction methodology that helps designers avoid excessive iterations and expensive respins. An actual view of what is being built can allow designers to visualize their layout stack-up based on zones. With an accurate picture, designers can perform more accurate DRCs, receive better feedback, and provide better data to the MCAD tool for fabrication (Figure 5).

Since there are many different materials and different rules a PCB designer needs to deal with, enabling and specifying rules for the combination of layers should be intuitive and easy. A simple step-by-step process (Figure 6) involves:

• Selecting the layer by choosing the desired checkbox in the layer matrix
• Selecting the rule
• Setting the value
• Defining a label that means something to the designer
• Setting the DRC display layer
• Adding a description for the rule (rules should be preserved in the tool) 

Users should be able to run inter-layer checks online or offline and in batch mode. When running the checks online, the user simply sets the rules and should be able to run the DRC and view DRC results.

Most EDA tools have long supported rigid-flex PCB designs. Ideally, the latest versions of these tools need to address new challenges stemming from multiple board layers, while providing a wide breadth and depth of in-design checks covering more than 30 new native flex and surface finishes layers (Figures 7 and 8). Users should also be able to incorporate their own layers for the tool to check, so they don’t have to wait for tool updates.

Cadence’s Allegro® 17.2 PCB design portfolio automates inter-layer, in-design checks in rigid-flex PCBs, providing the capabilities discussed in this section. By allowing you to perform DRCs for various non-electrical flex layers, the tool helps to save time and avoid respins. The tool also supports real-time concurrent team design, so multiple PCB designers can work on the same PCB design database.

How much time a PCB designer can save using the rigid-flex design capability versus performing manual DRCs (and going through iterations with the fabricator) is proportional to the complexity of the design. Aside from time savings, another benefit from using the capability is the ability to prevent omissions or other errors that could impact PCB design quality and overall cost. After all, problems that are discovered by the fabricator will naturally be more costly and time consuming to resolve due to the rework and iterations needed.

Page 3 of 4

• < Previous Page
• Next Page >