A hybrid non-threaded run-to-run control and incorporation of multiphysics models into semiconductor virtual metrology

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Publication Type dissertation
School or College College of Engineering
Department Chemical Engineering
Author Wang, Shijing
Title A hybrid non-threaded run-to-run control and incorporation of multiphysics models into semiconductor virtual metrology
Date 2016
Description In order to ensure high production yield of semiconductor devices, it is desirable to characterize intermediate progress towards the final product by using metrology tools to acquire relevant measurements after each sequential processing step. The metrology data are commonly used in feedback and feed-forward loops of Run-to-Run (R2R) controllers to improve process capability and optimize recipes from lot-to-lot or batch-to-batch. In this dissertation, we focus on two related issues. First, we propose a novel non-threaded R2R controller that utilizes all available metrology measurements, even when the data were acquired during prior runs that differed in their contexts from the current fabrication thread. The developed controller is the first known implementation of a non-threaded R2R control strategy that was successfully deployed in the high-volume production semiconductor fab. Its introduction improved the process capability by 8% compared with the traditional threaded R2R control and significantly reduced out of control (OOC) events at one of the most critical steps in NAND memory manufacturing. The second contribution demonstrates the value of developing virtual metrology (VM) estimators using the insight gained from multiphysics models. Unlike the traditional statistical regression techniques, which lead to linear models that depend on a linear combination of the available measurements, we develop VM models, the structure of which and the functional interdependence between their input and output variables are determined from the insight provided by the multiphysics describing the operation of the processing step for which the VM system is being developed. We demonstrate this approach for three different processes, and describe the superior performance of the developed VM systems after their first-of-a-kind deployment in a high-volume semiconductor manufacturing environment.
Type Text
Publisher University of Utah
Subject non-threaded; process control; R2R controller; run-to-run control; semiconductor manufacturing; virtual metrology
Dissertation Name Doctor of Philosophy
Language eng
Rights Management ©Shijing Wang
Format Medium application/pdf
Format Extent 2,755,587 bytes
Identifier etd3/id/4318
ARK ark:/87278/s6g76p2q
Setname ir_etd
Date Created 2016-10-13
Date Modified 2018-04-16
ID 197863
Reference URL https://collections.lib.utah.edu/ark:/87278/s6g76p2q
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