Automation and statistical process control of a single wafer etcher in a manufacturing environment

Etch processing equipment has become increasingly complicated and precise etch control has become more critical as device geometry shrinks. To meet this challenge, internal microprocessors are currently used to control wafer handling, lot and wafer logistics, processing and process control, and maintenance functions. Recently, external systems have been developed to provide additional monitoring and control capabilities. This paper addresses the automation of a single wafer etch platform that can be used for polysilicon, oxide, or metal etching. In addition to the main processing chamber, the vacuum load locks can be configured for pre-etch or post-etch processes. The system microprocessor and existing SECS II software package make the tool a good candidate for external automation and statistical process control (ASPC). This paper will discuss two automation packages currently in use at Motorola´s MOS6 wafer fab. The first automation package is a family of diagnostic and planned maintenance (PM) tools that interface with the etcher. The automation tools perform real time statistical process control on the wafers as they are processed. The second tool used for ASPC is the Cell Controller. The Cell Controller is a local recipe management system used to download recipes and recipe information to the etcher. A description of the software tools and the implementation in manufacturing will be presented. Techniques used for problem identification, troubleshooting and the status of the project are discussed.