KIOXIA Leads the Way in Optimizing Simulation Verification: A Deep Dive into PrimeSim HT and VC Execution Manager

In today’s fast-evolving semiconductor industry, the need for rapid, reliable, and resource-efficient verification processes has never been greater. As products become more sophisticated and demands for higher performance, density, and lower costs intensify, companies are increasingly turning to innovative solutions to manage the growing complexity and expense of simulation verification. At a recent technical event, Mr. Sawada from KIOXIA Corporation shared valuable insights into how his company is tackling these challenges head-on, leveraging Synopsys’ PrimeSim HT and VC Execution Manager to streamline verification workflows and optimize computational resources.

KIOXIA, a global leader in memory and SSD technology, operates at the cutting edge of flash memory development. The company’s product lineup spans diverse applications, but the development of advanced flash memory chips presents unique verification challenges. As Mr. Sawada explained, flash memory involves mixed-signal circuits—integrating both digital and analog elements. The memory cells themselves are complex, and multi-level technologies like TLC (Triple-Level Cell) and QLC (Quad-Level Cell) require precise analog control. This, in turn, makes SPICE simulations indispensable for accurate verification.

However, the relentless push for higher performance, lower costs, and greater memory density means that the design and verification cycles are becoming more frequent and iterative. KIOXIA has embraced an agile development methodology, allowing for rapid prototyping and continuous improvement. While this approach enables the company to quickly respond to market demands, it also leads to a significant increase in the number of verification runs, resulting in mounting simulation costs and resource demands.

To address these issues, KIOXIA has implemented a dual-pronged strategy: reducing simulation time and optimizing the use of computational resources. The two main tools at the heart of this strategy are Synopsys’ PrimeSim HT and VC Execution Manager.

PrimeSim HT: Accelerating Simulation Without Compromising Accuracy

PrimeSim HT is a new feature within the PrimeSim suite, designed to accelerate SPICE simulations by leveraging Liberty timing libraries. Traditionally, all circuit regions, whether digital or custom, are analyzed at the transistor level, which is computationally intensive. PrimeSim HT introduces the concept of H-models, which convert Liberty data into input-output tables for simulation. This allows digital and certain custom circuits to be simulated much faster, while maintaining SPICE-level accuracy.

Mr. Sawada shared results from KIOXIA’s internal evaluations, where PrimeSim HT was used to convert roughly 50% of transistors to H-models. This led to a 1.7x speed-up in pre-layout simulations and a 1.4x speed-up in post-layout scenarios. Importantly, the pass/fail results matched those of traditional SPICE simulations, confirming that the acceleration did not come at the expense of accuracy or functional integrity.

PrimeSim HT also addresses several operational challenges inherent in AMS (Analog Mixed-Signal) verification. By eliminating the need for D/A and A/D conversion tuning and resolving boundary issues between Verilog and SPICE, the tool simplifies the setup and management of large regression test suites. The ability to toggle HT on or off easily enables more frequent regression cycles, leading to faster bug detection and improved development agility.

VC Execution Manager: Smarter Resource Utilization

The second pillar of KIOXIA’s optimization strategy is VC Execution Manager, a comprehensive job management and verification platform. In agile environments, verification jobs can surge unpredictably, leading to resource bottlenecks and delays. KIOXIA’s teams often faced peaks in job submissions, particularly at the end of the week, which resulted in pending jobs and delayed feedback.

To address this, KIOXIA collaborated with Synopsys to develop a utility that enforces job execution limits per team or project. This approach maintains flexibility within teams but prevents resource spikes that can stall the entire verification process. VC Execution Manager enables automated scheduling, dynamic job allocation, and reservation of computational slots for high-priority or short-duration jobs. The result is a flatter job execution profile, improved predictability, and more efficient use of available resources.

Moreover, VC Execution Manager provides robust result aggregation and debugging capabilities, making it easier for teams to share outcomes, analyze failures, and iterate quickly. By managing resources at a granular level and automating much of the job submission process, KIOXIA has been able to maintain high verification throughput without overwhelming its infrastructure.

KIOXIA’s experience with PrimeSim HT and VC Execution Manager highlights the importance of adopting zero-code, tool-based solutions to address verification complexity. Rather than relying on manual scripting or ad-hoc resource management, the company has shown that integrated platforms can deliver both speed and reliability at scale.

Looking ahead, Mr. Sawada expressed optimism about further expanding the use of H-models in PrimeSim HT, potentially increasing H-model conversion ratio beyond the current 50%. He also called for native implementation of the resource management utility within VC Execution Manager, which would simplify setup and make these benefits accessible to a wider user base.

KIOXIA’s collaborative approach with Synopsys underscores the value of strong vendor partnerships in driving innovation. With continued support, the company aims to refine its verification processes even further, ensuring that its agile development style remains both high-quality and cost-effective.

As semiconductor design continues to evolve, the lessons from KIOXIA’s journey are clear: strategic investment in advanced verification tools can yield substantial returns in speed, resource efficiency, and overall product quality. By embracing solutions like PrimeSim HT and VC Execution Manager, KIOXIA is setting a benchmark for others in the industry, demonstrating that the right mix of technology and process can turn verification challenges into opportunities for innovation.