The increase in complexity and data rates encountered in high-end computer systems requires larger, more accurate, and higher-bandwidth model generation for system performance evaluations. Modeling tools need to allow noise-free designs with fast turn-around times for many iterations in the design cycle, in addition to good productivity through interfaces to CAD tools and standard file formats.

The IBM® Electromagnetic Field Solver Suite of Tools meets these needs. It includes full-wave two-dimensional and three-dimensional and quasi-static two-dimensional and three-dimensional tools, which are robust and accurate electromagnetic (EM) solvers for large problems. These solvers have unique features not otherwise available in the industry. The IBM Electromagnetic Field Solver Suite of Tools generates models for the signal and noise integrity analyses of critical system paths in order to afford multi-GHz operation.

The newer tools in the suite use advanced hierarchical algorithms with the full-wave, method-of-moment approach; unique, iterative solutions; advanced, and physics-based meshing. They have a long history of validation with measurements on a wide range of representative structures. Most of the tools have been used for many years with only rectangular geometry; the arbitrary-shape capability is a recent enhancement.

The IBM suite provides consistency between tools by using the same basis functions: They have automatic gridding with projection and proximity effects; they allow high-dimensional aspect ratios; they use iterative solutions that are always guaranteed to converge; and they provide guaranteed, causal, frequency-dependent extraction with the Debye algorithm for di-electric losses.

Complex, arbitrary shapes found in typical high-end computer server packages are discretized using automatic unique meshing, and the full-wave electric field or quasi-static current and charge distributions are calculated. From these calculations, the characteristic circuit parameter extraction of resistance R(f), inductance L(f), capacitance C(f), and conductance G(f) are made and then used in circuit simulations to predict system performance.

The fast algorithms have shown more than 100 times speed-up in capacitance over commercial tools, 60 times speed-up in full-wave analysis over typical method-of-moment approaches, and 12 times reduction in required memory.

All tools are given in executable form and can run on Linux® Red Hat 9.1 with 32-bit and 64-bit Fortran compilers. Documentation and example cases are included. The package is provided at no charge.

How does it work?

The suite uses an easy-to-learn, common GUI, but command access is via common file format, and API input and output is available. Also provided are interfaces to Cadence Allegro, Catia/ProE, HSPICE, Spectre, Ultrasim, and Touchstone formats. A simple, command-based framework, AMOC, is provided for modeling and simulation flow for parameterized sensitivity analyses.

The tools are as follows:

• LCGEN is a quasi-static, three-dimensional solver for inductance L and capacitance C for rectangles and a limited number of in-plane, diagonal rectangles. It includes PEEC formulation; it has built in autogridding and automatic topology generation; it handles high-dimensional aspect ratios; and a maximum of 100,000 inductive bars have been shown.
• RGEN is a three-dimensional resistance solver for DC analysis with an advanced iterative solution for large, resistive networks. It handles rectangular shapes; 64 million nodes have been demonstrated; and results can be given as current, voltage, power, or equivalent network.
• RSURF is a three-dimensional resistance solver for DC analysis with an advanced iterative solution for large, resistive networks. It calculates DC solution for arbitrary shape structures composed of zero-thick surfaces, and results can be given as voltage or equivalent network. 14 million nodes have been demonstrated.
• EMSIM is a 3D, full-wave, frequency-domain, method-of-moment, electromagnetic solver. It calculates electric and magnetic fields, current distribution, or input impedance. It handles rectangular shapes, and it has a robust, advanced, iterative solution. 20,000 unknowns using 10 GB of memory have been shown, 40,000 with reduced-coupling technique. This tool uses physics-based autogridding and has a built-in FFT to calculate time-domain waveforms. It can handle extreme, dimensional aspect ratios and multiple dielectrics (but the dielectric volume that can be handled is generally limited to about ten cubic wavelengths).
• EMITPKG, which is built on the EMSIM algorithm, provides R(f)L(f)C(f)G(f) parameters per unit length for transmission lines with three-dimensional features through novel end-effect extraction procedure; this feature is not available from commercial tools. EMITPKG has the same features as EMSIM.
• PROPCALC is a 3D, full-wave frequency-domain method-of-moment, eigenvalue based electromagnetic solver that can provide R(f)L(f)C(f)G(f) parameters per unit length for periodic features; includes advanced iterative solution; best used for mesh planes, homogeneous and inhomogeneous waveguides.
• EMSURF is a three-dimensional full-wave, frequency-domain, method-of-moment, electromagnetic solver. It uses a surface impedance-based solution and produces many fewer unknowns than commercial, volume-based solvers. It includes an advanced, accelerated, hierarchical, iterative solution, and it can solve about 15,000 unknowns per one GB of memory. Over 200,000 surface unknowns have been shown on complex structures and 1.5 million surface unknowns (75 million volume unknowns) on parallel distributed-memory BlueGene supercomputer platform with 16,000 nodes. This tool has automatic gridding and handles uniform dielectrics. Arbitrary shapes are represented as quadrilaterals and triangles. It has a built-in Debye algorithm for dielectric loss; wave and lumped port capability; and built-in FFT for calculating time-domain waveforms. It can handle extreme, dimensional aspect ratios, and it has distributed as well as hybrid parallel/distributed server solving capability. It shows a 200 to 1000-time speed-up over EMSIM and 15 to 50-time reduction in required memory.
• EMSURF_TL built on EMSURF algorithm, provides R(f)L(f)C(f)G(f) parameters per unit length for transmission lines with three-dimensional features; this feature is not available from commercial tools; same features with EMSURF. This tool is available only upon request.
• CSURF is a hierarchical capacitance solver for large number of unknowns and multiple dielectrics. It operates ten to 175 times faster than LCGEN and commercial tools; 150,000 unknowns have been shown; and an API interface is available.
• AMOC is the Advanced Model Creator that provides a framework for modeling and simulation flow control with parameterized sensitivity analysis for any of the above tools in the suite. It uses command line calls.
• EIP-GUI is a motif-based, 3D, graphical user interface common for all the tools. It includes three-dimensional editing and viewing; various plotting facilities for results; and interfaces to Allegro and Catia CAD tools. All tools can send output to the industry-standard Touchstone file format. Also supported are output formats for SPICE, HSPICE, Ultrasim, and Spectre circuit simulators.
• CZ2D is a two-dimensional extractor for R(f)L(f)C(f)G(f) parameters per unit length for transmission lines with guaranteed causal properties. This tool uses an advanced algorithm that includes dielectrics, and it has a finite/method-of-moment hybrid algorithm. It handles rectangles and right triangles; it includes automatic projection, skin-effect, and proximity gridding; and it uses industry-standard output file formats. API input capability is available.
• AQUAIA (All Questions About Interconnects Answered) is the most advanced on-chip analysis tool on the market; AQUAIA was pioneered by IBM in 2002. It can perform frequency-dependent transmission line analysis, R(f)L(f)C, unlike the simple RC analysis practiced by most tools in the industry. The tool extracts the per-unit length parameters of any layer in a large on-chip wiring stack based on actual processing layers and dimensions using IBM's advanced, built-in, 2D and 3D EIP full-wave electromagnetic field solvers, CZ2D, EMITPKG, and CSURF. Unlike generally available extractors, the EIP tools allow the easy per-unit-length calculation of parameters for structures with 3D features that results in extremely rapid calculations for many sensitivity analyses. In addition, the 3D capacitance calculation is performed with the hierarchical CSURF solver that has been shown to be more than 100x faster than commercially available tools. The results are then directly fed into the built-in circuit simulator to put out performance parameters such as delay, rise time, crosstalk, common-mode noise, and eye diagram. The tool can also perform statistical analysis and optimization of dimensions and performance for signal lines, wide data-bus, I/O lines, or clock distribution applications.
• ChipJoule is an automatic, multi-physics, general-purpose framework for thermal analysis of packages and interconnections. It can be used for very large problem sizes with input directly from CAD layout and with full details of metals and dielectrics found in the actual hardware. It uses various thermal boundary conditions of constant temperature, heat density, or current flow and can put out temperature distribution and equivalent thermal circuit for SPICE simulations. It can be expanded for coupled electro-thermal simulations. It uses RGEN and RSURF and accepts Cadence .cif files.

Barry J. Rubin, Ph.D., is a research staff member at IBM""s T. J. Watson Research Center, N.Y. He formerly worked on the circuit design of CMOS and charge-coupled devices and then in electrical package analysis, doing pioneering work on the understanding and calculation of signal propagation and delta-I noise in single and multi-chip ceramic modules. Dr. Rubin later focused on electromagnetic techniques: He developed the first rigorous technique for calculating the propagation parameters for signal lines and other features situated in a mesh plane environment (embodied in PropCalc code); he developed the approach for using two-dimensional rooftop functions to model volume polarization effects (PropCalc and EMSIM); he developed comprehensive techniques using physically-based gridding to automatically refine meshes for conductor proximity effects (EMSIM, LCGen, and CZ2D); and he co-invented the robust technique for handling inhomogeneous structures in CZ2D. More recently, he developed reduced-coupling and other advanced techniques for handling large problems. Dr. Rubin""s work appears in numerous conference and journal articles. He has mentored dozens of engineers and interns, and he holds an IBM Fifth Plateau Invention Achievement Award.

Jason Morsey, Ph.D., is a research staff member in the Interconnect and Packaging Analysis group at IBM""s T. J. Watson Research Center. He is the current Electrical Interconnect and Packaging chairman on the IBM Professional Interest Community. His research interests include computational electromagnetics and fast electromagnetic solvers, modeling of high-speed interconnects, packaging analysis, and signal integrity analysis.

Lijun Jiang, Ph.D., is a research staff member at IBM""s T. J. Watson Research Center. His research interests focus on the signal integrity analysis, computational electromagnetics, EMC, antenna analysis and design, numerical methods, and more. Dr. Jiang received the IEEE MTT-S Graduate Fellowship Award in 2003 and the Y. T. Lo Outstanding Research Award in 2004. He is a member of IEEE and of Sigma Xi. He serves as the reviewer of IEEE Transactions on Antenna and Propagation and IEEE Transactions on Advanced Packaging.

Lon Eisenberg develops GUIs, interfaces, and data and graphic formatting. He supports customers and is in charge of system configurations, subscription and support, and releases.

Alina Deutsch""s biography is available at her other technology on alphaWorks.