Abstract: Methods and processes to reduce the cost and cycle time of designing manufacturing flows are described, particularly for microelectronic integrated circuit processes. One embodiment of the present invention is a method which divides the task of designing process flows into a number of abstraction levels and provides mechanisms to translate between these levels of abstraction. The process is divided into a number of modules each having process constraints. Process constraints are propagated backwards from the final module to the first module, and may also be propagated forward from earlier modules to later modules of needed. This approach results in a top-down design methodology where requirements from higher levels of abstraction are successively reduced to lower abstraction levels, while meeting the constraints imposed by the lower levels.