A process control methodology applied to manufacturing GaAs MMIC's

A methodology for guiding process-driven manufacturing organizations in instituting process control on a facility-wide basis is proposed. The methodology begins with defining a specific process and the customer's expectations of this process, then increases control over the process through four levels: measurable, predictable, acceptable, and recoverable. An application of this methodology to the control of submicron-gate lithography on a GaAs monolithic microwave integrated circuit (MMIC) process is discussed. Experience suggests that the realization of process control is as much a managerial problem as it is a technical one. This application suggests that the proposed methodology serves as a useful conceptual guideline for operators, engineers, and managers in uniformly applying a wide variety of process control tools. >