1 July 2003 Multiloop photolithography control using hierarchical context information for APC models
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Automated process control loops running in semiconductor manufacturing facilities must be able to compensate for machine variations as well as identify differences between products. With a number of exposure tools, pattern levels, and active devices manufactured in a typical ASIC fab, for photo APC system must maintain thousands of control loops. Control loop context information in TI's Semiconductor Manufacturing System (SMS) is defined in a hierarchal fashion which allows default values in a manufacturing specification to be overridden for particular products or lots. ProcessWORKS APC software automatically adds new control loops for new devices and pattern levels to a defined model structure. This system scales well and supports hundreds of thousands of control loops from a single database server in TI fabs. Application of product specific control systems for alignment and exposure control has provided increased exposure capacity due to decreased reworks and setup time, a substantial reduction in engineering maintenance and improved process capability. The APC system has evolved into a requirement for leading edge photolithography processes in Texas Instruments.
© (2003) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
John D. Stuber, John D. Stuber, } "Multiloop photolithography control using hierarchical context information for APC models", Proc. SPIE 5044, Advanced Process Control and Automation, (1 July 2003); doi: 10.1117/12.485309; https://doi.org/10.1117/12.485309

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