A control-to-target architecture for process control

Sullivan, M.; Butler, Stephanie Watts; Hirsch, J.; Wang, C.J.

doi:10.1109/66.286850

Cited by 11 publications

(2 citation statements)

References 12 publications

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“…[6][7][8][9][10] Simultaneous work went into process modeling. 13 With the preliminary foundations established, control theory for the semiconductor industry was developed, and algorithms mainly incorporating a RtR approach were implemented. 12 Control architecture was another topic of research.…”

Section: B Backgroundmentioning

confidence: 99%

Run to run control in tungsten chemical vapor deposition using H2/WF6 at low pressures

Sreenivasan

Gougousi

et al. 2001

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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Thickness metrology and end point control in W chemical vapor deposition process from SiH 4 / WF 6 using in situ mass spectrometry Influence of gas composition on wafer temperature in a tungsten chemical vapor deposition reactor: Experimental measurements, model development, and parameter identification Process diagnostics and thickness metrology using in situ mass spectrometry for the chemical vapor deposition of W from H 2 / WF 6 Run to run control with an Internal Model Control ͑IMC͒ approach has been used for wafer state ͑thickness͒ control in the tungsten chemical vapor deposition ͑CVD͒ process. The control implementation was preceded by establishing a stable wafer state thickness metrology using in situ mass spectrometry. Direct reactor sampling was achieved from an Ulvac ERA-1000 cluster tool module during the H 2 /WF 6 W CVD process at 0.5 Torr for temperatures 350-400°C using a 300 amu closed ion source Inficon Transpector system. Signals from HF product generation were used for in-process thickness metrology and compared to ex situ, postprocess thickness measurements obtained by microbalance mass measurements, providing a metrology accuracy of about 7% ͑limited primarily by the very low conversion efficiency of the process used, ϳ2%-3%͒. A deliberate systematic process drift was introduced as a Ϫ5°C temperature change for each successive wafer, which would have led to a major ͑ϳ50%͒ thickness decrease over ten wafers in an open loop system. A robust run to run ͑RtR͒ control algorithm was used to alter the process time in order to maintain constant HF sensing signal obtained from the mass spectrometer, resulting in thickness control comparable to the metrology accuracy. The efficacy of the control algorithm was also corroborated by additional experiments that utilized direct film weight measurements through the use of the microbalance. A set of simulations in Matlab ® preceded the control implementation and helped in tuning the controller parameters. These results suggest that in situ chemical sensing, and particularly mass spectrometry, provide the basis for wafer state metrology as needed to achieve RtR control. Furthermore, since the control was consistent with the metrology accuracy, we anticipate significant improvements for processes used in manufacturing, where conversion rates are much higher ͑40%-50%͒ and corresponding signals for metrology will be much larger.

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Section: B Backgroundmentioning

confidence: 99%

Run to run control in tungsten chemical vapor deposition using H2/WF6 at low pressures

Sreenivasan

Gougousi

et al. 2001

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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“…Considerable work has been done to formalize this procedure, including the MIT run-by-run Controller [2], Ultramax™ [3], and Texas Instrument's PCC Controller [6][4] [5].…”

Section: Introductionmentioning

confidence: 99%

A control system for photolithographic sequences

Leang

Thomson

et al. 1996

IEEE Trans. Semicond. Manufact.

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The goal of our control system is to improve the reliability, accuracy, and economy of operation of a sequence of interrelated processes. We achieve this task by using well known, rigorous statistical techniques to continuously monitor process parameters, detect out-of-control equipment, and then optimally adjust relevant machine inputs to bring the process back on target. We have implemented the supervisory control system on the photolithography sequence in the Berkeley Microfabrication Laboratory, where it has been conclusively proven that the supervisory control system increases significantly the capability of the entire process. The supervisory control algorithms, consisting of feedback and feed-forward control, multivariate, model-based statistical process control (SPC), and automated specification management algorithms, are independent of machine and/or process, and can be applied to any semiconductor manufacturing sequence.

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Moore’s Law Increasing Complexity, and the Limits of Organization: The Modern Significance of Japanese Chipmakers’ Commodity DRAM Business

Chuma

Hashimoto

2009

Dynamics of Knowledge, Corporate Systems and Innovation

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A control-to-target architecture for process control

Cited by 11 publications

References 12 publications

Run to run control in tungsten chemical vapor deposition using H2/WF6 at low pressures

Run to run control in tungsten chemical vapor deposition using H2/WF6 at low pressures

A control system for photolithographic sequences

Moore’s Law Increasing Complexity, and the Limits of Organization: The Modern Significance of Japanese Chipmakers’ Commodity DRAM Business

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