47
H-Matrix-Based Finite-Element-Based Thermal Analysis for 3D ICs
HAI-BAO CHEN, Shanghai Jiao Tong University
YING-CHI LI, The University of Hong Kong
SHELDON X.-D. TAN and XIN HUANG, University of California, Riverside
HAI WANG, University of Electronic Science and Technology of China
NGAI WONG, The University of Hong Kong
In this article, we propose an efficient finite-element-based (FE-based) method for both steady and transient
thermal analyses of high-performance integrated circuits based on the hierarchical matrix (H-matrix) rep-
resentation. H-matrix has been shown to provide a data-sparse way to approximate the matrices and their
inverses with almost linear-space and time complexities. In this work, we apply the H-matrix concept for
solving heating diffusion problems modeled by parabolic partial differential equations (PDEs) based on the
finite element method. We show that the matrix from a FE-based steady and transient thermal analysis can
be represented by H-matrix without any approximation, and its inverse and Cholesky factors can be evalu-
ated by H-matrix w ith controlled accuracy. We then show and prove that the memory and time complexities
of the solver are bounded by O(k
1
N log N)andO(k
2
1
N log
2
N), respectively, where k
1
is a small quantity de-
termined by accuracy requirements and N is the number of unknowns in the system. The comparison with
existing product-quality LU solvers, CSPARSE and UMFPACK, on a number of 3D IC thermal matrices,
shows that the new method is much more memory efficient than these methods, which however prevents
CPU time comparison with those methods on large examples. But the proposed method can solve all the
given thermal circuits with decent scalabilities, which shows good agreement with the predicted theoretical
results.
Categories and Subject Descriptors: J.6 [Computer Application]: Computer-Aided Engineering—
Computer-aided design (CAD)
General Terms: Design, Algorithm
Additional Key Words and Phrases: Finite element method, integrated circuits, H-matrix, thermal analysis
ACM Reference Format:
Hai-Bao Chen, Ying-Chi Li, Sheldon X.-D. Tan, Xin Huang, Hai Wang, and Ngai Wong. 2015. H-matrix-based
finite-element-based thermal analysis for 3d ICs. ACM Trans. Des. Autom. Electron. Syst. 20, 4, Article 47
(September 2015), 25 pages.
DOI: http://dx.doi.org/10.1145/2714563
1. INTRODUCTION
Continuous process scaling and aggressive device integration lead to rapid power den-
sity increase and adverse thermal effects. This problem becomes more severe as the
VLSI technology scales to the nanometer ranges. Excessively high on-chip tempera-
ture can cause many severe problems such as reduced reliability of chips, thermal and
This work is supported in part by NSF grant under No. CCF-1017090, in part by NSF Grant under No. CCF-
1255899, in part by NSF Grant under No. CCF-1527324, in part by Semiconductor Research Corporation
(SRC) grant under No. 2013-TJ-2417, in part by the Hong Kong Research Grants Council under the GRF
Projects 718711E and 718213E, in part by the Nature Science Foundation of China (NSFC) under No.
61404024, in part by 985 research funds from Shanghai Jiao Tong University and University of Electronic
Science and Technology of China.
Corresponding author: Sheldon X.-D. Tan; email: stan@ece.ucr.edu.
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DOI: http://dx.doi.org/10.1145/2714563
ACM Transactions on Design Automation of Electronic Systems, Vol. 20, No. 4, Article 47, Pub. date: September 2015.