<title>Photocluster control system implementation at the IBM Advanced Semiconductor Technology Center</title>

Abstract

i. AbstractPhotocluster control is a key problem in advanced microelectronic manufacturing. As ground rules shrink, sustaining optimum overlay and critical dimension performance requires the frequent updating of tool settings dependent on product, product level, and statistically significant tool/process variation. The system we describe here relies on bi..directional SECSII interfaces to both exposure and metrology tools for upload/download of tool settings, measurement and logistics data. Exposure tool and process specific models are employed to predict dose, focus and overlay settings for each lot in queue at the exposure tool, based on prior lot or send-ahead wafer metrology data. The alignment and exposure of each lot is then executed under host control, following the automated download of the appropriate settings.

<title>Knowledge-based APC methodology for overlay control</title>

“…This means that the update can be significant and have a direct effect on production work in progress (WIP). By applying APC to the control of exposure tools, "Tool Level APC", frequent small updates can be made to the tool baseline in order to minimize the impact on production WIP 3,4 .…”