IEEE transactions on computer-aided design of integrated circuits and systems : a publication of the IEEE Circuits and Systems Society

As minimum feature size and pitch spacing further decrease, triple patterning lithography (TPL) is a possible 193nm extension along the paradigm of double patterning lithography (DPL). However, there is very little study on TPL layout decomposition. In this paper, we show that TPL layout decomposition is a more difficult problem than that for DPL. We then propose a general integer linear programming formulation for TPL layout decomposition which can simultaneously minimize conflict and stitch numbers. Since ILP has very poor scalability, we propose three acceleration techniques without sacrificing solution quality: independent component computation, layout graph simplification, and bridge computation. For very dense layouts, even with these speedup techniques, ILP formulation may still be too slow. Therefore, we propose a novel vector programming formulation for TPL decomposition, and solve it through effective semidefinite programming (SDP) approximation. Experimental results show that the ILP with acceleration techniques can reduce 82% runtime compared to the baseline ILP. Using SDP based algorithm, the runtime can be further reduced by 42% with some tradeoff in the stitch number (reduced by 7%) and the conflict (9% more). However, for very dense layouts, SDP based algorithm can achieve 140× speed-up even compared with accelerated ILP.

/pdf/layout-decomposition-for-triple-patterning-lithography-1bak910stu.pdf

Layout decomposition for triple patterning lithography

Early routability prediction helps designers and tools perform preventive measures so that design rule violations can be avoided in a proactive manner. However, it is a huge challenge to have a predictor that is both accurate and fast. In this work, we study how to leverage convolutional neural network to address this challenge. The proposed method, called RouteNet, can either evaluate the overall routability of cell placement solutions without global routing or predict the locations of DRC (Design Rule Checking) hotspots. In both cases, large macros in mixed-size designs are taken into consideration. Experiments on benchmark circuits show that RouteNet can forecast overall routability with accuracy similar to that of global router while using substantially less runtime. For DRC hotspot prediction, RouteNet improves accuracy by 50% compared to global routing. It also significantly outperforms other machine learning approaches such as support vector machine and logistic regression.

https://dl.acm.org/doi/pdf/10.1145/3240765.3240843

RouteNet: routability prediction for mixed-size designs using convolutional neural network

In double patterning lithography (DPL) layout decomposition for 45 nm and below process nodes, two features must be assigned opposite colors (corresponding to different exposures) if their spacing is less than the minimum coloring spacing. However, there exist pattern configurations for which pattern features separated by less than the minimum coloring spacing cannot be assigned different colors. In such cases, DPL requires that a layout feature be split into two parts. We address this problem using two layout decomposition approaches based on a conflict graph. First, node splitting is performed at all feasible dividing points. Then, one approach detects conflict cycles in the graph which are unresolvable for DPL coloring, and determines the coloring solution for the remaining nodes using integer linear programming (ILP). The other approach, based on a different ILP problem formulation, deletes some edges in the graph to make it two-colorable, then finds the coloring solution in the new graph. We evaluate our methods on both real and artificial 45 nm test-cases. Experimental results show that our proposed layout decomposition approaches effectively decompose given layouts to satisfy the key goals of minimized line-ends and maximized overlap margin. There are no design rule violations in the final decomposed layout.

/pdf/layout-decomposition-approaches-for-double-patterning-417p7ou71s.pdf

Layout Decomposition Approaches for Double Patterning Lithography

Photonic technology is becoming an increasingly attractive solution to the problems facing today's electronic chip-scale interconnection networks. Recent progress in silicon photonics research has enabled the demonstration of all the necessary optical building blocks for creating extremely high-bandwidth density and energy-efficient links for on-chip and off-chip communications. From the feasibility and architecture perspective however, photonics represents a dramatic paradigm shift from traditional electronic network designs due to fundamental differences in how electronics and photonics function and behave. As a result of these differences, new modeling and analysis methods must be employed in order to properly realize a functional photonic chip-scale interconnect design. In this paper, we present a methodology for characterizing and modeling fundamental photonic building blocks which can subsequently be combined to form full photonic network architectures. We also describe a set of tools which can be utilized to assess the physical-layer and system-level performance properties of a photonic network. The models and tools are integrated in a novel open-source design and simulation environment. We present a case study of two different photonic networks-on-chip to demonstrate how our improved understanding and modeling of the physical-layer details of photonic communications can be used to better understand the system-level performance impact.

/pdf/physical-layer-modeling-and-system-level-design-of-chip-3e8ahiqn11.pdf

Physical-Layer Modeling and System-Level Design of Chip-Scale Photonic Interconnection Networks

In this paper, we present a fast and accurate lithographic hotspot detection flow with a novel MLK (Machine Learning Kernel), based on critical feature extraction and classification. In our flow, layout binary image patterns are decomposed/analyzed and critical lithographic hotspot related features are defined and employed for low noise MLK supervised training. Combining novel critical feature extraction and MLK supervised training procedure, our proposed hotspot detection flow achieves over 90% detection accuracy on average and much smaller false alarms (10% of actual hotspots) compared with some previous work [9, 13], without CPU time overhead.

/pdf/machine-learning-based-lithographic-hotspot-detection-with-4xsojwyei3.pdf

Machine learning based lithographic hotspot detection with critical-feature extraction and classification

In this paper we present EPIC, an efficient and effective predictor for IC manufacturing hotspots in deep sub-wavelength lithography. EPIC proposes a unified framework to combine different hotspot detection methods together, such as machine learning and pattern matching, using mathematical programming/optimization. EPIC algorithm has been tested on a number of industry benchmarks under advanced manufacturing conditions. It demonstrates so far the best capability in selectively combining the desirable features of various hotspot detection methods (3.5–8.2% accuracy improvement) as well as significant suppression of the detection noise (e.g., 80% false-alarm reduction). These characteristics make EPIC very suitable for conducting high performance physical verification and guiding efficient manufacturability friendly physical design.

EPIC: Efficient prediction of IC manufacturing hotspots with a unified meta-classification formulation

Under real and continuously improving manufacturing conditions, lithography hotspot detection faces several key challenges. First, real hotspots become less but harder to fix at post-layout stages; second, false alarm rate must be kept low to avoid excessive and expensive post-processing hotspot removal; third, full chip physical verification and optimization require fast turn-around time. To address these issues, we propose a high performance lithographic hotspot detection flow with ultra-fast speed and high fidelity. It consists of a novel set of hotspot signature definitions and a hierarchically refined detection flow with powerful machine learning kernels, ANN (artificial neural network) and SVM (support vector machine). We have implemented our algorithm with industry-strength engine under real manufacturing conditions in 45nm process, and showed that it significantly out-performs previous state-of-the-art algorithms in hotspot detection false alarm rate (2.4X to 2300X reduction) and simulation run-time (5X to 237X reduction), meanwhile archiving similar or slightly better hotspot detection accuracies. Such high performance lithographic hotspot detection under real manufacturing conditions is especially suitable for guiding lithography friendly physical design.

High performance lithographic hotspot detection using hierarchically refined machine learning

Under the real and evolving manufacturing conditions, lithography hotspot detection faces many challenges. First, real hotspots become hard to identify at early design stages and hard to fix at post-layout stages. Second, false alarms must be kept low to avoid excessive and expensive post-processing hotspot removal. Third, full chip physical verification and optimization require very fast turn-around time. Last but not least, rapid technology advancement favors generic hotspot detection methodologies to avoid exhaustive pattern enumeration and excessive development/update as technology evolves. To address the above issues, we propose a high performance hotspot detection methodology consisting of: 1) a fast layout analyzer; 2) powerful hotspot pattern identifiers; and 3) a generic and efficient flow with successive performance refinements. We implement our algorithms with industry-strength engine under real manufacturing conditions and show that it significantly outperforms state-of-the-art algorithms in false alarms (2.4X to 2300X reduction) and runtime (5X to 237X reduction), meanwhile achieving similar or better hotspot accuracies. Compared with pattern matching, our method achieves higher prediction accuracy for hotspots that are not previously characterized, therefore, more detection generality when exhaustive pattern enumeration is too expensive to perform a priori. Such high performance hotspot detection is especially suitable for lithography-friendly physical design.

Duo Ding

Papers

Layout decomposition for triple patterning lithography

Machine learning based lithographic hotspot detection with critical-feature extraction and classification

EPIC: Efficient prediction of IC manufacturing hotspots with a unified meta-classification formulation

High performance lithographic hotspot detection using hierarchically refined machine learning

High Performance Lithography Hotspot Detection With Successively Refined Pattern Identifications and Machine Learning