Shift left with Calibre interactive symmetry checking to improve design efficiency

By Sara Khalaf

Symmetry plays a crucial role in IC design by ensuring balanced device behavior, minimizing mismatch, and improving yield. However, validating symmetry has traditionally been a tedious and time-consuming process. Many designers find themselves spending valuable time manually checking layouts or writing complex validation rules, only to discover symmetry-related issues late in the design cycle—sometimes even after fabrication.

With Calibre interactive symmetry checking, designers now have a powerful tool to catch symmetry issues early, directly within their design environment. This solution allows verification tasks to shift left, making it easier to detect and fix problems during the design phase rather than waiting until signoff or post-manufacturing. The result is fewer iterations, reduced rework, and faster time to tape-out. This solution is fully automated, completely code free and requires a couple of clicks.

The challenges of traditional symmetry checking methods

Traditional methods for symmetry validation come with several limitations that can lead to inefficiencies and delays. Below are some commonly used techniques and their drawbacks:

• Manual ruler measurements: Designers manually measure distances and placements to confirm symmetry. This approach is not only slow and painstaking, but it’s also prone to human error—critical measurements may be missed, leading to issues discovered too late in the design process.
• Writing custom rules: Some designers attempt to write custom rules to validate symmetry, but doing so requires extensive coding knowledge and experience. This method is often too complex and time-consuming to be practical in fast-paced design environments.
• Cell mirroring assumptions: In some workflows, symmetry is assumed to be correct by construction. However, slight shifts in cell placement can disrupt symmetry, introducing subtle issues that might not be detected without validation.
• Parasitic extraction for resistance matching: Some designers rely on matching resistance values to infer symmetry. However, this method has limitations, as extraction engines make approximations in their calculations, which can mask potential symmetry issues.

These traditional methods often result in symmetry problems being identified late in the design cycle—during signoff or, worse, after fabrication. At that point, fixing these issues can require time-consuming rework and expensive iterations, jeopardizing schedules and increasing costs.

Shift left verification with Calibre interactive symmetry checking

The Calibre interactive symmetry checking solution changes the game by enabling early and easy symmetry validation. In the Calibre nmPlatform toolsuite, advanced symmetry matching can be interactively invoked using the Calibre RealTime Custom interface so designers can interactively validate symmetry at any point during the design process, helping them shift verification left. This early-stage validation helps identify and address symmetry-related issues when they are easiest to fix—long before they become costly problems.

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Key features of the Calibre interactive symmetry checking

The Calibre interactive symmetry checking solution offers several key features that streamline the verification process:

1. No coding required: Designers no longer need advanced coding skills to validate symmetry. The tool is fully automated and can be run with just a few clicks, reducing the complexity of the verification process.
2. Interactive validation: The tool is embedded within the design environment, allowing designers to select specific areas of the layout and validate symmetry on the fly. Results are available instantly within the design environment, making it easier to identify and fix issues.
3. Early detection at any design stage: Unlike signoff tools that require a fully LVS-clean design, Calibre’s solution can be used at any point in the design process. This flexibility allows designers to catch and resolve issues early, reducing the number of design iterations required.
4. Parallel DRC validation: With its integration into Calibre RealTime, the symmetry checker can run in parallel with design rule checking (DRC). This ensures that designs are not only symmetric but also DRC-clean, further streamlining the verification process.

Conclusion

The Calibre interactive symmetry checking solution offers a revolutionary approach to symmetry validation by enabling designers to shift verification left and address issues early in the design cycle. With a no-code, fully automated tool integrated directly into the design environment, symmetry validation becomes easy, efficient, and accessible to all designers.

By reducing design iterations, accelerating time to tape-out, and improving design quality, Calibre helps teams meet their goals while minimizing effort and costs. With Calibre interactive symmetry checking, designers can focus on what matters most—delivering high-quality designs on time and on budget.

Ready to experience the benefits of shifting left with Calibre? Click here to download our latest whitepaper and learn more about how Calibre interactive symmetry checking can transform your design flow!