Real-time plasma etch control using in-situ sensors and neural networks

Stokes, D.; May, G.S.

doi:10.1109/cca.1999.807760

Cited by 1 publication

(1 citation statement)

References 7 publications

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“…The authors report an 83% improvement in etch depth results compared to a purely timed etch. A model-based feedback controller is reported in [68] and [100], controlling etch rate, which is measured using laser inferometry and a profilometer. Manipulated variables are pressure, RF power, and gas flow, and a linear LQG/LTR controller is compared to a nonlinear adaptive controller based on a neural network model.…”

Section: ) Control Of Etch Variablesmentioning

confidence: 99%

Estimation and Control in Semiconductor Etch: Practice and Possibilities

Ringwood

Lynn

Bacelli

et al. 2010

IEEE Trans. Semicond. Manufact.

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Abstract-Semiconductor wafer etching is, to a large extent, an open-loop process with little direct feedback control. Most silicon chip manufacturers rely on the rigorous adherence to a "recipe" for the various etch processes, which have been built up based on considerable historical experience. However, residue buildup and difficulties in achieving consistent preventative maintenance operations lead to drifts and step changes in process characteristics. This paper examines the particular technical difficulties encountered in achieving consistency in the etching of semiconductor wafers and documents the range of estimation and control techniques currently available to address these difficulties. An important feature of such an assessment is the range of measurement options available if closed-loop control is to be achieved.Index Terms-Closed-loop control, plasma etch, run-to-run control, semiconductor wafer, state estimation, virtual metrology.

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Section: ) Control Of Etch Variablesmentioning

confidence: 99%