Recent trends in the integration of process, device and circuit modeling tools and the current rapid emergence of UNIX® based computing environments of networked workstations and compute engines makes possible user-friendly, taskbased CAD systems for technology optimization, characterization and cell design. The paper discusses these trends and identifies opportunities to leverage Technology CAD tools in the development of competitive technologies and products.
i I:This paper describes how tools for technology CAD, in use at AT&T Bell Laboratories, arc integrated into a task-based system designed to meet the needs of IC technology development and circuit design for optimization, characterization, and verification. TCAD is the name given to this system and it is made up of state-of-the-art, user-friendly modeling tools. These tools include those for process, device and circuit simulation, parameter extraction and optimization.The TCAD environment is UNIX. The highest level of TCAD is a user interface program, tcad, written in C and shell, tcad is easily ported across UNIX systems so the investment in development is protected and efforts are not duplicated. It monitors access and usage patterns, tracks tasks routinely performed, has electronic communication facilities between users and program developers and provides various levels of restricted-access for certain sensitive or beta-stage tools and technology files. Provision is made to capture input files to add to the regression data-base, or when tools terminate abnormally. TCAD tools can be used independently or coupled together to form tasks.The TCAD system is open to the integration of a variety of tools including exploratory products and the primary TCAD tools are accurate, flexible, robust and user-friendly. Some of these primary tools are described in the next section. The philosophy behind the TCAD architecture is outlined in the third section. Much of the power of TCAD comes from UNIX through networking and distributed computing. These features of UNIX and their impact on TCAD arc described in Section 4. Several examples of TCAD tasks and concluding remarks are given in the fifth and sixth sections, respectively.
The Building Blocks for TCADTCAD leverages current predictive tools for process to cell level design. Some of these tools are described below including the process simulator BICEPS-5.0, the device simulator MEDUSA, the statistical process/device simulator FABRICS, the parameter extractor ARTHUR, the circuit simulator ADVICE and the optimizer CENTER.
The Process Simulator BICEPS-5.0BICEPS-5.0 is a modular two-dimensional process simulator that retains the coordinate transformation philosophy of the original code [4]. It contains models for ion implantation, predeposition, drive-in in inert and oxidizing ambients, epitaxy, etching and deposition. The diffusion equation is solved using finite differences. Improvements over the original code include new physical models, an improved user interface, a new graphic package and new numerical methods.The i...