Parasitic Extraction

What Is Parasitic Extraction?

Parasitic extraction (PEX) is a critical process in electronic design automation (EDA) that involves removing unwanted resistive, capacitive, and inductive elements inadvertently introduced into a design during manufacturing. Parasitic extraction assists designers in comprehending the impact of physical implementation on the functionality of their ideal logic and circuits. Parasitic extraction is becoming increasingly important as designers seek to enhance functionality by stacking dies. To guarantee that timing specifications are achieved, it's essential to comprehend and simulate the intricate interconnect arrangements employed in these integration methods. Efforts to address these complex challenges are already underway. Broadly, parasitic extraction is used to find:

• Noise coupling
• IR drop
• Chip behavior

Why Is Parasitic Extraction Important?

The performance of SoCs can be significantly impacted by parasitic elements, resulting in problems such as signal delay, power loss, and crosstalk between signals. The influence of parasitic elements becomes more noticeable with the adoption of advanced nodes and the growing complexity of SoCs, making parasitic extraction even more essential. For instance, in 3D-IC design, verifying the parasitic effects between components and interconnects on multiple processes is necessary to minimize cost. Further, the introduction of FinFETs has increased the parasitic interactions between the neighboring geometries. Interconnect wiring parasitics have become dominant parameters influencing circuit performance in deep sub-micron technologies as device dimensions reduce and circuit speed increases. Accurate parasitic extraction is essential for several reasons:

Performance Optimization: It allows designers to predict and optimize an SoC’s performance by understanding how parasitic elements influence signal speed and integrity.

Power Efficiency: By identifying parasitic resistances and capacitances, designers can make informed decisions to minimize power consumption.

Reliability: Parasitic extraction helps identify potential reliability issues like electromigration, which parasitic resistances can exacerbate.

Design Verification is a crucial step in the verification process. The linchpin ensures the physical design aligns with the electrical specifications. It's not merely a step but necessary to create reliable and efficient ICs.

Challenges in Parasitic Extraction

Parasitic extraction involves a tradeoff between accuracy and computing resources. As processes become denser, finding this balance becomes more challenging due to increased complexity and the use of more gates in average designs. Parasitic extraction is essential to ensure performance, reliability, and power efficiency and involves many challenges, such as:

• As new process nodes have evolved, the interconnect resistance and lateral line coupling have grown, causing higher RC delays.
• Increasing the number of dummy fills leads to increasing extraction elements.
• FinFET adoption has increased complexity by introducing effects like device-width quantization.
• As designs become more intricate, the sheer volume of parasitic data can be overwhelming, necessitating efficient data-handling techniques.
• Variations in the manufacturing process can affect parasitic elements, requiring robust modeling techniques to account for these variations.

Parasitic Extraction with Cadence

Silicon advances have undoubtedly created new opportunities for product differentiation, but not without some unpredictability and uncertainty. Often, schematic creation (electrical), layout (physical), and verification steps are performed sequentially, with little or no visibility into the consequences of each physical design decision. Cadence offers a variety of parasitic extraction tools for different types of flows.

Cadence Quantus Extraction Solution is the industry’s most trusted parasitic extraction tool for digital and custom/analog flows. The tool features massively parallel architecture for performance and scalability across hundreds of CPUs, providing the fastest single-corner and multi-corner runtimes compared to other methodologies. The Quantus Extraction Solution is a production-proven signoff extraction tool ideal for all nodes, including advanced nodes and FinFET designs. The solution includes a built-in 3D capacitance random-walk field solver, Quantus Field Solver. By delivering higher accuracy parasitics, the tool helps to reduce overall design cycle times and significantly enhances the quality of silicon in complex designs. Integrated with the Cadence Innovus Implementation System and Virtuoso Studio, the Quantus solution is the most complete and efficient path to accurate parasitic extraction for all mainstream and advanced-node designs, including FinFET. Furthermore, it is tightly integrated with the Cadence Tempus Timing Solution to provide the fastest convergence and up to 3X reduction in overall timing signoff flow turnaround time. It is also tightly integrated with the Voltus-XFi Custom Power Integrity Solution for electromigration (EM) and IR drop analysis, ensuring accuracy for FinFET designs.

Cadence Quantus Field Solver is a built-in 3D capacitance field solver offered with the Quantus Extraction Solution. The Quantus Field Solver provides a breakthrough in 3D parasitic extraction by introducing cloud-ready and massively parallel architecture that significantly improves the performance of 3D field solvers while allowing designers to achieve the accuracy of a 3D field solver. This random-walk-based field solver can handle any capacity, providing faster turnaround times and best-in-class accuracy.

Cadence Virtuoso Layout Suite for electrically aware design (EAD) lets design teams monitor electrical issues while creating a layout. Rather than waiting until the layout is completed before verifying that it meets the original design intent, engineers can analyze, simulate, and verify interconnect decisions in real time to generate an electrically correct layout by construction.

Start optimizing your parasitic extraction process with Cadence today.