Stephen W. Director – författare

One of the keys to success in the IC industry is getting a new product to market in a timely fashion and being able to produce that product with sufficient yield to be profitable. There are two ways to increase yield: by improving the control of the manufacturing process and by designing the process and the circuits in such a way as to minimize the effect of the inherent variations of the process on performance. The latter is typically referred to as "design for manufacture" or "statistical design". As device sizes continue to shrink, the effects of the inherent fluctuations in the IC fabrication process will have an even more obvious effect on circuit performance. And design for manufacture will increase in importance. We have been working in the area of statistically based computer aided design for more than 13 years. During the last decade we have been working with each other, and individually with our students, to develop methods and CAD tools that can be used to improve yield during the design and manufacturing phases of IC realization. This effort has resulted in a large number of publications that have appeared in a variety of journals and conference proceedings. Thus our motivation in writing this book is to put, in one place, a description of our approach to IC yield enhancement. While the work that is contained in this book has appeared in the open literature, we have attempted to use a consistent notation throughout this book.

This book describes a new type of computer aided VLSI design tool, called a VLSI System Planning, that is meant to aid designers dur­ ing the early, or conceptual, state of design. During this stage of design, the objective is to define a general design plan, or approach, that is likely to result in an efficient implementation satisfying the initial specifications, or to determine that the initial specifications are not realizable. A design plan is a collection of high level design decisions. As an example, the conceptual design of digital filters involves choosing the type of algorithm to implement (e. g. , finite impulse response or infinite impulse response), the type of polyno­ mial approximation (e. g. , Equiripple or Chebyshev), the fabrication technology (e. g. , CMOS or BiCMOS), and so on. Once a particu­ lar design plan is chosen, the detailed design phase can begin. It is during this phase that various synthesis, simulation, layout, and test activities occur to refine the conceptual design, gradually filling more detail until the design is finally realized. The principal advantage of VLSI System Planning is that the increasingly expensive resources of the detailed design process are more efficiently managed. Costly redesigns are minimized because the detailed design process is guided by a more credible, consistent, and correct design plan.

This book describes a new type of computer aided VLSI design tool, called a VLSI System Planning, that is meant to aid designers dur­ ing the early, or conceptual, state of design. During this stage of design, the objective is to define a general design plan, or approach, that is likely to result in an efficient implementation satisfying the initial specifications, or to determine that the initial specifications are not realizable. A design plan is a collection of high level design decisions. As an example, the conceptual design of digital filters involves choosing the type of algorithm to implement (e. g. , finite impulse response or infinite impulse response), the type of polyno­ mial approximation (e. g. , Equiripple or Chebyshev), the fabrication technology (e. g. , CMOS or BiCMOS), and so on. Once a particu­ lar design plan is chosen, the detailed design phase can begin. It is during this phase that various synthesis, simulation, layout, and test activities occur to refine the conceptual design, gradually filling more detail until the design is finally realized. The principal advantage of VLSI System Planning is that the increasingly expensive resources of the detailed design process are more efficiently managed. Costly redesigns are minimized because the detailed design process is guided by a more credible, consistent, and correct design plan.