Automated photolithography critical dimension controls in a complex, mixed technology, manufacturing fab

Abstract

Critical dimension control is one of the most difficult challenges in semiconductor manufacturing. In the photolithography area, factors associated with individual technologies, lithography tools, product levels, reticles, and specific product specifications dictate unique exposure conditions for each lithography tool setup. In a multi-partnumber, mixed technology environment, sophisticated controls are required to ensure that the correct exposure conditions are used for each wafer processed. A to manufacturing. A key feature of the system is its ability to learn the character of each reticle as well as the differences between each lithography tool. The initial exposure dose used for a new reticle is based on the normalization of data from similar reticles and known tool-to-tool differences. Factors saved for each tool may be adjusted to correct for maintenance activities that introduce significant shifts to a tool's historic exposure settings. Examples which demonstrate each of the major components of the controls system's capabilities will be presented.

The role of process system engineering (PSE) in integrated circuit (IC) manufacturing

“…Crisalle, Soper, Mellichamp, & Seborg, 1992), and local control, often in single-input single-output configuration (e.g. Schneider, Smyth, & Watts, 2001). Run to run (R2R) control is a form of discrete process control in which the product recipe is modified between runs or batches, to minimize the effects of process drifts, caused by factors such as the aging of the equipment or chemicals, and process shifts, often an outcome of upstream failures.…”