In advanced technology nodes, accurate glitch modeling is crucial for designing high-performance, energy-efficient, and reliable integrated circuits. In this work, we present a new approach for gate-level glitch propagation modeling, employing efficient Artificial Neural Networks (ANNs) to accurately estimate glitch shape characteristics, propagation delay, and power consumption. Moreover, we propose an iterative workflow that integrates our models into standard cell libraries, exploiting the available accuracy and size trade-off. Experimental results on gates implemented in 7 nm FinFET technology indicate that our ANNs exhibit a strong correlation with SPICE (R2over 0.99). Therefore, our approach could enable accurate full-chip glitch analysis and effectively guide glitch reduction techniques.

Multiple Input Switching (MIS) effects commonly induce undesired glitch pulses at the output of CMOS gates, potentially leading to circuit malfunction and significant power consumption. Thus, accurate and efficient glitch modeling is crucial for the design of high-performance, low-power, and reliable ICs. In this work, we present a new gate-level approach for modeling glitch effects under MIS. Unlike previous studies, we leverage efficient Machine Learning (ML) techniques to accurately estimate the glitch shape characteristics, propagation delay, and power consumption. To this end, we evaluate various ML engines and explore different Artificial Neural Network (ANN) architectures. Moreover, we introduce a seamless workflow to integrate our ANNs into existing standard cell libraries, striking an optimal balance between model size and accuracy in gate-level glitch modeling. Experimental evaluation on gates implemented in 7 nm FinFET technology demonstrates that the proposed models achieve an average error of 2.19% against SPICE simulation while maintaining a minimal memory footprint.

As integrated circuit technologies are moving to smaller technology nodes, Electromigration (EM) has become one of the most challenging problems facing the EDA industry. While numerical approaches have been widely deployed since they can handle complicated interconnect structures, they tend to be much slower than analytical approaches. In this paper, we present a fast semi-analytical approach, based on the matrix exponential, for the solution of Korhonen's stress equation at discrete spatial points of interconnect trees, which enables the analytical calculation of EM stress at any time and point independently. The proposed approach is combined with the extended Krylov subspace method to accurately simulate large EM models and accelerate the calculation of the final solution. Experimental evaluation on OpenROAD benchmarks demonstrates that our method achieves 0.5% average relative error over the COMSOL industrial tool while being up to three orders of magnitude faster.

With process technology scaling, accurate gate-level timing analysis becomes even more challenging. Highly resistive on-chip interconnects have an ever-increasing impact on timing, signals no longer resemble smooth saturated ramps, while gate-interconnect interdependencies are stronger. Moreover, efficiency is a serious concern since repeatedly invoking a signoff tool during incremental optimization of modern VLSI circuits has become a major bottleneck. In this paper, we introduce a novel machine learning approach for timing estimation of gate-level stages using current source models and the concept of multiple slew and effective capacitance values. First, we exploit a fast iterative algorithm for initial stage timing estimation and feature extraction, and then we employ four artificial neural networks to correlate the initial delay and slew estimates for both the driver and interconnect with golden SPICE results. Contrary to prior works, our method uses fewer and more accurate features to represent the stage, leading to more efficient models. Experimental evaluation on driver-interconnect stages implemented in 7 nm FinFET technology indicates that our method leads to 0.99% (0.90 ps) and 2.54% (2.59 ps) mean error against SPICE for stage delay and slew, respectively. Furthermore, it has a small memory footprint (1.27 MB) and performs 35× faster than a commercial signoff tool. Thus, it may be integrated into timing-driven optimization steps to provide signoff accuracy and expedite timing closure.

During the past decade, Model Order Reduction (MOR) has become key enabler for the efficient simulation of large circuit models. MOR techniques based on moment-matching are well established due to their simplicity and computational performance in the reduction process. However, moment-matching methods based on the ordinary Krylov subspace are usually inadequate to accurately approximate the original circuit behaviour. In this paper, we present a moment-matching method which is based on the extended Krylov subspace and exploits the superposition property in order to deal with many terminals. The proposed method can handle large-scale regular and singular circuits, and generate accurate and efficient reduced-order models for circuit simulation. Experimental results on industrial IBM power grid benchmarks demonstrate that our method achieves an error reduction up to 83.69% over a standard Krylov subspace technique.

As process geometries shrink below 45 nm, accurate and efficient gate-level timing analysis becomes even more challenging. Modern VLSI interconnects are more resistive, signals no longer resemble saturated ramps, and gate input pins exhibit a significant Miller effect. Over recent years, the semiconductor industry has adopted current source models (CSMs) for accurate gate modeling. Industrial gate models, however, are precharacterized assuming capacitive loads, which poses significant challenges to the approximation of the highly resistive load interconnect with an effective capacitance ( Ceff). In fact, most related works are either computationally expensive or unable to approximate the output slew. Furthermore, they require additional precharacterization and ignore the Miller effect. In this article, we present an iterative methodology for fast and accurate gate delay estimation. The proposed approach accurately computes the driver output waveform, using closed-form formulas to calculate a Ceffper waveform segment, while accounting for their interdependence. Thus, it allows for variable analysis resolution exploiting an accuracy/runtime tradeoff. In contrast to prior works, our approach is compatible with conventional CSMs and considers the impact of Miller capacitance. We evaluate our method on representative driver-load test circuits consisting of interconnects with arbitrary RC characteristics and ASU ASAP 7-nm standard cells. The proposed method achieves 1.3% and 2.5% delay and slew root-mean-square percentage error (RMSPE) against SPICE, respectively. In addition, it provides high efficiency, as it converges in 2.3 iterations on average.

Manufacturing process variation in sub-20nm processes has introduced ever increasing overhead in Static Timing Analysis (STA) in order to guarantee the reliable operation of the circuit. Chip designers apply corner-based analysis and add guard-bands to design parameters in order to take into account the impact of process variation on timing. However, the aforementioned techniques are either too slow as the number of design parameters proliferates with the integration of more components into a chip or inaccurate due to the assumption that the worst case delay resides at the corners of design parameters. In this paper, we present a novel statistical methodology, which relies on Extreme Value Theory (EVT), to estimate the worst case delay of VLSI circuits under variations in gate/interconnect parameters. Despite the previous statistical approaches toward maximum delay estimation, our methodology can be applied regardless of the underlying gate/interconnect delay model or any assumption about the distribution of the Arrival Time (AT) at every circuit node, making it very appealing for integration to any level of timing analysis abstraction (from spice-to-gate level) and provide fast yet accurate results. Experimental results on ISCAS85/ISCAS89 circuits show that the estimated maximum AT at the Primary Outputs (POs) can be within 5% of the true maximum AT, at the cost of a few thousand Monte Carlo simulations.