A generalized approach to vacuum system automation

Abstract

Computer automation of vacuum equipment has traditionally been dominated by custom hardware and software solutions, requiring long and expensive development periods. On-going modification and support of the installed computer equipment often requires an appreciable portion of a computer specialist’s time. In order to achieve a more cost effective approach, the authors have analyzed a variety of vacuum deposition and etching processes running on equipment supplied by numerous manufacturers. The following observations have led to the development of a generalized vacuum equipment automation system which requires minimal custom engineering time to install and support: (1) In spite of the high marketing profile given to RS-232, IEEE-488, and SECS II interfaces, by far the most common and easy to use interfaces provided by vacuum equipment vendors are simple digital and analog. (2) Most processes involve between 50 and 300 discrete or continuous parameters; however, few of these parameters vary at rates appreciably higher than 1 Hz. (3) The inter-relationships between these many parameters are often complex and/or difficult to specify in a fixed manner. The computer must therefore be capable of operating according to process logic entered and modified in the field by a process engineer, who may not be a computer specialist. (4) The skill level of vacuum operators varies from doctorate to grade school; uses of vacuum equipment vary from pure research to high-volume production. The user interface must therefore be highly adaptable yet easy to use.