Chia-Tung Ho

dblp:143/4616 · DBLP profile ↗
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16ranked-venue papers
6as first author
12since 2021 · last 2026
—ORCID · conflict

Domains — the database's venue-derived domains; a paper can count in several

Systems, architecture and hardware · 15 · 5 first-author · 11 since 2021Artificial intelligence and machine learning · 1 · 1 first-author · 1 since 2021Software engineering, systems software and programming languages · 1 · 1 since 2021Graphics, computer vision, multimedia, augmented reality and games · 1 · 1 first-author · 1 since 2021
YearPublicationVenuePosition
2026 Invited: Polymath: Self-Improving Hierarchical Workflow for Multi-Domain Problem Solving
abstract
Large language models (LLMs) excel at solving complex tasks by executing agentic workflows composed of detailed instructions and structured operations. However, building agents for diverse applications by manually embedding foundation models into agentic systems such as Chain-of-Thought, Self-Reflection, and ReACT through text interfaces limits scalability and efficiency. Recently, researchers have explored automating workflow generation using code-based representations, but most methods depend on labeled data, limiting their applicability to real-world, dynamic hardware design problems. We introduce Polymath, a self-improving agent with a dynamic hierarchical workflow that combines task flow graphs with code-represented workflows to address these challenges. Polymath employs an experience-driven optimization framework that integrates multi-level graph optimization using surrogate scores from historical evaluations with a self-reflection-guided evolutionary algorithm for workflow refinement, enabling unsupervised self-improvement without labeled data. Experiments show that Polymath outperforms a leading commercial agentic system by 16.23% pass@1 and 11.47% pass@3 on hardware benchmarks, and achieves an average 8.1% improvement over state-of-the-art baselines on coding, math, and multi-turn QA tasks.
Chia-Tung Ho, Abhishek B. Akkur, Haoxing Ren
ISPD1
2026 FVRuleLearner: Operator-Level Reasoning Tree (Op-Tree)-Based Rules Learning for Formal Verification
Lily Jiaxin Wan, Chia-Tung Ho, Yunsheng Bai, Cunxi Yu, Deming Chen, Haoxing Ren
VTS2
2025 VerilogCoder: Autonomous Verilog Coding Agents with Graph-based Planning and Abstract Syntax Tree (AST)-based Waveform Tracing Tool
abstract
Due to the growing complexity of modern Integrated Circuits (ICs), automating hardware design can prevent a significant amount of human error from the engineering process and result in less errors. Verilog is a popular hardware description language for designing and modeling digital systems; thus, Verilog generation is one of the emerging areas of research to facilitate the design process. In this work, we propose VerilogCoder, a system of multiple Artificial Intelligence (AI) agents for Verilog code generation, to autonomously write Verilog code and fix syntax and functional errors using collaborative Verilog tools (i.e., syntax checker, simulator, and waveform tracer). Firstly, we propose a task planner that utilizes a novel Task and Circuit Relation Graph retrieval method to construct a holistic plan based on module descriptions. To debug and fix functional errors, we develop a novel and efficient abstract syntax tree (AST)-based waveform tracing tool, which is integrated within the autonomous Verilog completion flow. The proposed methodology successfully generates 94.2% syntactically and functionally correct Verilog code, surpassing the state-of-the-art methods by 33.9% on the VerilogEval-Human v2 benchmark.
Chia-Tung Ho, Haoxing Ren, Brucek Khailany
AAAI1
2025 ChipVQA: Benchmarking Visual Language Models for Chip Design
abstract
Large-language models (LLMs) have exhibited great potential to assist chip designs and analysis. Recent research and efforts are mainly focusing on text-based tasks including general QA, debugging, design tool scripting, and so on. However, chip design and implementation workflow usually require a visual understanding of diagrams, flow charts, graphs, schematics, waveforms, etc, which demands the development of multimodality foundation models. In this paper, we propose ChipVQA, a benchmark designed to evaluate the capability of visual language models for chip design. ChipVQA includes 142 carefully designed and collected VQA questions covering five chip design disciplines: Digital Design, Analog Design, Architecture, Physical Design and Semiconductor Manufacturing. Unlike existing VQA benchmarks, ChipVQA questions are carefully designed by chip design experts and require indepth domain knowledge and reasoning to solve. We conduct comprehensive evaluations on both open-source and proprietary multimodal models that are greatly challenged by the benchmark suit. ChipVQA is available at https://github.com/phdyang007/chipvqa.
Qijing Huang 0001, Nathaniel Ross Pinckney, Walker J. Turner, Wenfei Zhou, Yanqing Zhang 0002, Chia-Tung Ho, Chen-Chia Chang, Haoxing Ren
DATE7
2025 DRC-Coder: Automated DRC Checker Code Generation Using LLM Autonomous Agent
abstract
In the advanced technology nodes, the integrated design rule checker (DRC) is often utilized in place and route tools for fast optimization loops for power-performance-area. Implementing integrated DRC checkers to meet the standard of commercial DRC tools demands extensive human expertise to interpret foundry specifications, analyze layouts, and debug code iteratively. However, this labor-intensive process, requiring to be repeated by every update of technology nodes, prolongs the turnaround time of designing circuits. In this paper, we present DRC-Coder, a multi-agent framework with vision capabilities for automated DRC code generation. By incorporating vision language models and large language models (LLM), DRC-Coder can effectively process textual, visual, and layout information to perform rule interpretation and coding by two specialized LLMs. We also design an auto-evaluation function for LLMs to enable DRC code debugging. Experimental results show that targeting on a sub-3nm technology node for a state-of-the-art standard cell layout tool, DRC-Coder achieves perfect F1 score 1.000 in generating DRC codes for meeting the standard of a commercial DRC tool, highly outperforming standard prompting techniques (F1=0.631). DRC-Coder can generate code for each design rule within four minutes on average, which significantly accelerates technology advancement and reduces engineering costs.
Chen-Chia Chang, Chia-Tung Ho, Yiran Chen 0001, Haoxing Ren
ISPD2
2024 DGR: Differentiable Global Router
abstract
Modern VLSI design flows necessitate fast and high-quality global routers. In this paper, we introduce DGR, a differentiable global router capable of concurrent optimization for hundreds of thousands of nets 1. Our innovation lies in the development of a routing Directed Acyclic Graph (DAG) forest to represent the 2D pattern routing space for all nets, enabling coordinated selection of Steiner trees and 2-pin routing paths from a global perspective. For efficient search within the DAG forest, we relax the discrete search space to be continuous and develop a differentiable solver accelerated by deep learning toolkits on GPUs. Experimental results demonstrate that DGR substantially mitigates routing overflow while concurrently reducing total wirelengths from 0.95% to 4.08% and via numbers from 1.28% to 2.54% in congested testcases compared to state-of-the-art academic global routers. Additionally, DGR exhibits favorable scalability in both runtime and memory with respect to the number of nets.
Wei Li 0159, Rongjian Liang, Anthony Agnesina, Chia-Tung Ho, Anand Rajaram, Haoxing Ren
DAC5
2024 Novel Transformer Model Based Clustering Method for Standard Cell Design Automation
abstract
Standard cells are essential components of modern digital circuit designs. With process technologies advancing beyond 5nm, more routability issues have arisen due to the decreasing number of routing tracks (RTs), increasing number and complexity of design rules, and strict patterning rules. The standard cell design automation framework is able to automatically design standard cell layouts, but it is struggling to resolve the severe routability issues in advanced nodes. As a result, a better and more efficient standard cell design automation method that can not only resolve the routability issue but also scale to hundreds of transistors to shorten the development time of standard cell libraries is highly needed and essential.
Chia-Tung Ho, Ajay Chandna, David Guan, Alvin Ho, Haoxing Ren
ISPD1
2023 NVCell 2: Routability-Driven Standard Cell Layout in Advanced Nodes with Lattice Graph Routability Model
abstract
Standard cells are essential components of modern digital circuit designs. With process technologies advancing beyond the 5nm node, more routability issues have arisen due to the decreasing number of routing tracks, increasing number and complexity of design rules, and strict patterning rules. Automatic standard cell synthesis tools are struggling to design cells with severe routability issues. In this paper, we propose a routability-driven standard cell synthesis framework using a novel pin density aware congestion metric, lattice graph routability modelling approach, and dynamic external pin allocation methodology to generate routability optimized layouts. On a benchmark of 94 complex and hard-to-route standard cells, NVCell 2 improves the number of routable and LVS/DRC clean cell layouts by 84.0% and 87.2%, respectively. NVCell 2 can generate 98.9% of cells LVS/DRC clean, with 13.9% of the cells having smaller area, compared to an industrial standard cell library with over 1000 standard cells.
Chia-Tung Ho, Alvin Ho, Matthew Fojtik, Shang Wei, Brucek Khailany, Haoxing Ren
ISPD1
2022 Net Separation-Oriented Printed Circuit Board Placement via Margin Maximization
abstract
Packaging has become a crucial process due to the paradigm shift of More than Moore. Addressing manufacturing and yield issues is a significant challenge for modern layout algorithms. We propose to use printed circuit board (PCB) placement as a benchmark for the packaging problem. A maximum-margin formulation is devised to improve the separation between nets. Our framework includes seed layout proposals, a coordinate descent-based procedure to optimize routability, and a mixed-integer linear programming method to legalize the layout. We perform an extensive study with 14 PCB designs and an open-source router. We show that the placements produced by NS-place improve routed wirelength by up to 25%, reduce the number of vias by up to 50%, and reduce the number of DRVs by 79% compared to manual and wirelength-minimal placements.
Chung-Kuan Cheng, Chia-Tung Ho, Chester Holtz
ASP-DAC2
2022 Machine Learning Prediction for Design and System Technology Co-Optimization Sensitivity Analysis
abstract
As technology nodes continue to advance relentlessly, geometric pitch scaling starts to slow down. In order to retain the trend of Moore’s law, design technology co-optimization (DTCO) and system technology co-optimization (STCO) are introduced together to continue scaling beyond 5 nm using pitch scaling, patterning, and novel 3-D cell structures [i.e., complementary-FET (CFET)]. However, numerous DTCO and STCO iterations are needed to continue block-level area scaling with considerations of physical layout factors: 1) various standard cell (SDC) library sets (i.e., different cell heights and conventional FET); 2) design rules (DRs); 3) back end of line (BEOL) settings; and 4) power delivery network (PDN) configurations. The growing turnaround time (TAT) among SDC design, DR optimization, and block-level area evaluation becomes one of the major bottlenecks in DTCO and STCO explorations. In this work, we develop a machine learning model that combines bootstrap aggregation and gradient boosting techniques to predict the sensitivity of minimum valid block-level area of various physical layout factors. We first demonstrate that the proposed model achieves 16.3% less mean absolute error (MAE) than the previous work for testing sets. Then, we show that the proposed model successfully captures the block-level area sensitivity of new SDC library sets, new BEOL settings, and new PDN settings with 0.013, 0.004, and 0.027 MAE, respectively. Finally, compared to the previous work, the proposed approach improves the robustness of predicting new circuit designs by up to 6.76%. The proposed framework provides more than$100\times $speedup compared to conventional DTCO and STCO exploration flows.
Chung-Kuan Cheng, Chia-Tung Ho, Chester Holtz, Daeyeal Lee, Bill Lin 0001
IEEE Trans. Very Large Scale Integr. Syst.2
2021 SP&R: SMT-Based Simultaneous Place-and-Route for Standard Cell Synthesis of Advanced Nodes
abstract
In this article, we propose an automated standard cell synthesis framework, SP&R, which simultaneously solves P&R without deploying any sequential/separate operations, by a novel dynamic pin allocation scheme. The proposed SP&R utilizes the multiobjective optimization feature of satisfiability modulo theories (SMT) to obtain optimal cell layouts. To achieve practical scalability of the framework, we develop various search-space reduction techniques, including breaking symmetry, conditional assignment/localization, and cell/objective function partitioning. Compared to the previous work, SP&R achieves 20.8× to 131.7× runtime improvements on average across the design-rule sets. As a result, SP&R successfully produces cell layouts up to 36 field-effect transistors (FETs) and 27 nets within 1.75 h by orchestrating all innovative tactics together, resulting in the generation of a whole 7-nm standard cell library. Compared to the known layouts, our work improves cell size and # M2 tracks by 0.1 contacted poly pitch and 0.3 tracks, respectively.
Daeyeal Lee, Dongwon Park, Chia-Tung Ho, Ilgweon Kang, Hayoung Kim, Sicun Gao, Bill Lin 0001, Chung-Kuan Cheng
IEEE Trans. Comput. Aided Des. Integr. Circuits Syst.3
2021 Complementary-FET (CFET) Standard Cell Synthesis Framework for Design and System Technology Co-Optimization Using SMT
abstract
With the relentless scaling of technology nodes, design technology co-optimization (DTCO) for the conventional (Conv.) cell structure is starting to reach its limitations due to limited routing resources, lateral p-n separations, and performance requirements. As a result, system technology co-optimization (STCO) has been proposed to exploit the benefits of 3-D architectures. Complementary-FET (CFET) technology, which stacks p-FET on n-FET or vice versa, can release the restriction of p-n separation and reduce in-cell routing congestion by enabling p-n direct connections. However, CFET standard cell (SDC) synthesis demands holistic considerations to maximize the area benefit of scaling at the block level due to the extremely limited routability that comes from the stacked structure and reduced cell height. In this article, we propose a satisfiability modulo theory (SMT)-based CFET SDC synthesis framework that simultaneously solves place-and-route to generate optimized layouts. We first demonstrate that the CFET structure achieves 10.94% and 21.27% reduction on average cell area and metal length, respectively, and 15.10% smaller block-level area compared to Conv. structure as scaling down to 3.5T architecture. For routability, the proposed constraint-based minimum pin length/minimum pin opening and objective-based edge-based pin-separation/M2 track use reduce up to 48% #DRVs at the block level compared to the previous work. Then, through extensive DTCO explorations on ground design rules and #BEOLs, 3.5T CFET SDCs achieve up to 6.50% smaller block-level areas than 4.5T CFET SDCs. Finally, with the assistance of STCO and DTCO, 3.5T CFET SDCs achieve 21.0% on average reduced block-level areas compared to 4.5T Conv. SDCs.
Chung-Kuan Cheng, Chia-Tung Ho, Daeyeal Lee, Bill Lin 0001, Dongwon Park
IEEE Trans. Very Large Scale Integr. Syst.2
2020 A Routability-Driven Complimentary-FET (CFET) Standard Cell Synthesis Framework using SMT
abstract
As the technology node is evolving, standard cell (SDC) design scaling is obstructed by design constraints such as limited routing resources, lateral P-N separation, and performance requirements. Complimentary-FET (CFET) technology, which stacks the P-FET on N-FET or vice versa, is able to release the restriction of P-N connection for SDC layout scaling. However, (both in-cell and block-level) routable CFET SDC design, while maintaining the scaling advantages, is a non-trivial problem because of the extremely limited routability (including pin-accessibility) comes from the intrinsic stacked FET structure.
Chung-Kuan Cheng, Chia-Tung Ho, Daeyeal Lee, Dongwon Park
ICCAD2
2019 IncPIRD: Fast Learning-Based Prediction of Incremental IR Drop
abstract
The on-chip power delivery network (PDN) is an essential element of physical implementation that strongly determines functionality, quality and reliability of a given IC product. To meet IR drop requirements, a denser power grid is desirable. On the other hand, to meet timing and layout density requirements, a sparser power grid leaves more resources for routing. Often, numerous time-consuming iterations among PDN design, IR analysis, and floorplanning or placement are needed during the physical implementation of modern high-performance designs. Thus, fast and accurate incremental IR prediction has emerged as a critical need, as it can potentially reduce the turnaround time between design and analysis and help improve design convergence. In this work, we apply superposition and partitioning techniques to extract relevant electrical features of a given SOC floorplan and PDN. We then use a machine learning model to predict the updated static IR drop for each power node (having tap current source attached) in the design throughout a series of changes (PDN modification, block movement, block power change, power pad movement) to the SOC floorplan, without needing to rerun a golden IR drop tool. We develop our model with more than 150 generated SOC floorplans with different PDN structures in 28nm foundry technology. Compared to an industry-leading, golden IR drop signoff tool (ANSYS RedHawk), we achieve 20-1000× speedup with less than 1 mV average absolute error and approximately 5m V maximum absolute error.
Chia-Tung Ho, Andrew B. Kahng
ICCAD1
2017 InTraSim: Incremental Transient Simulation of Power Grids
abstract
Effective transient power grid simulators are needed during design processes because a designed power grid needs to be numerously analyzed. This paper builds an efficient and reliable incremental power grid transient simulator, which we name it InTraSim, by integrating macro modeling techniques, sparse recovery mechanisms, an innovated pseudo-node value estimation method, and an initiated adaptive error control scheme. InTraSim is able to deal with not only element-value alterations of designs but also topology modifications of designs.
Yu-Min Lee, Chia-Tung Ho
IEEE Trans. Comput. Aided Des. Integr. Circuits Syst.2
2014 Incremental transient simulation of power grid
abstract
The power grid needs to be frequently analyzed during the design process of power distribution network. Hence, an effective method being able to capture its transient behavior is desired for designers.
Chia-Tung Ho, Yu-Min Lee, Shu-Han Wei, Liang-Chia Cheng
ISPD1