Dr. David J. Johnson Profile

Dr. David J. Johnson

Manager/Research & Development at Oerlikon USA Inc

SPIE Involvement:

Author

Publications (15)

Proceedings Article | 7 March 2007 Paper

Plasma etching of positively sloped silicon structures

Shouliang Lai, Ken Mackenzie, Dave Johnson, Russ Westerman

Proceedings Volume 6462, 646209 (2007) https://doi.org/10.1117/12.714780

KEYWORDS: Etching, Silicon, Polymers, Plasma etching, Photomasks, Metals, Plasma, Anisotropic etching, Chemistry, Semiconducting wafers

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Proceedings Article | 20 October 2006 Paper

Controlling CD uniformity for 45nm technology node applications

J. Plumhoff, S. Srinivasan, R. Westerman, D. Johnson, C. Constantine

Proceedings Volume 6349, 63490A (2006) https://doi.org/10.1117/12.686390

KEYWORDS: Etching, Photomasks, Chromium, Binary data, Critical dimension metrology, Plasma, Control systems, Ions, Lithography

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Proceedings Article | 23 January 2006 Paper

Endpoint detection method for time division multiplex etch processes

Russ Westerman, Dave Johnson, Shouliang Lai, Mike Teixeira

Proceedings Volume 6109, 61090I (2006) https://doi.org/10.1117/12.646498

KEYWORDS: Etching, Plasma, Silicon, Time division multiplexing, Signal processing, Semiconducting wafers, Plasma etching, Spectroscopy, Chemical analysis, Signal to noise ratio

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Proceedings Article | 28 June 2005 Paper

Quartz etch process for alternating aperture phase shift masks (alt-APSM)

Sunil Srinivasan, Russ Westerman, Jason Plumhoff, Dave Johnson, Chris Constantine

Proceedings Volume 5853, (2005) https://doi.org/10.1117/12.617095

KEYWORDS: Etching, Quartz, Photomasks, Phase shifts, Chromium, Chemistry, Dry etching, Plasma, Scanning electron microscopy, Photoresist processing

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Proceedings Article | 22 January 2005 Paper

Notch reduction in silicon on insulator (SOI) structures using a time division multiplex etch processes

Shouliang Lai, Sunil Srinivasan, Russell Westerman, Dave Johnson, John Nolan

Proceedings Volume 5715, (2005) https://doi.org/10.1117/12.582764

KEYWORDS: Etching, Silicon, Microelectromechanical systems, Time division multiplexing, Plasma, Semiconducting wafers, Multiplexing, High aspect ratio silicon micromachining, Oxides, Ions

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Proceedings Article | 6 December 2004 Paper

Quartz etch process to improve etch depth linearity and uniformity using Mask Etcher IV

Sunil Srinivasan, Jason Plumhoff, Russ Westerman, Dave Johnson, Chris Constantine

Proceedings Volume 5567, (2004) https://doi.org/10.1117/12.571468

KEYWORDS: Etching, Photomasks, Quartz, Scanning electron microscopy, Reactive ion etching, Phase shifts, Dry etching, Lithography, Manufacturing, Surface roughness

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Proceedings Article | 30 December 2003 Paper

Advanced pressure control in time division multiplexed (TDM) plasma etch processes

Shouliang Lai, Russ Westerman, Dave Johnson, John Nolan

Proceedings Volume 5342, (2003) https://doi.org/10.1117/12.521910

KEYWORDS: Etching, Time division multiplexing, Plasma etching, Silicon, Plasma, Control systems, Process control, Manufacturing, Microelectromechanical systems, Multiplexing

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Proceedings Article | 15 January 2003 Paper

Scalloping minimization in deep Si etching on Unaxis DSE tools

Shouliang Lai, Dave Johnson, Russ Westerman, John Nolan, David Purser, Mike Devre

Proceedings Volume 4979, (2003) https://doi.org/10.1117/12.472750

KEYWORDS: Etching, Silicon, Switching, Time division multiplexing, Microelectromechanical systems, Plasma, Microsoft Foundation Class Library, Manufacturing, Plasma etching, Polymers

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Proceedings Article | 27 December 2002 Paper

Comparison of endpoint methods in advanced photomask etch applications

David Johnson, Jason Plumhoff, Jong Shin, Emmanuel Rausa

Proceedings Volume 4889, (2002) https://doi.org/10.1117/12.467749

KEYWORDS: Chromium, Etching, Spectroscopy, Signal processing, Plasma, Electronic filtering, Sinc filters, Photomasks, Sensors, Reflectivity

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Proceedings Article | 3 September 1999 Paper

New optical sensor for real-time in-situ end point monitoring during dry etching of III-V ternary multistack layers

Kevin Liddane, Ramdane Benferhat, Jewon Lee, Russell Westerman, David Johnson, John Donohue, Jay Sasserath, Stephen Pearton

Proceedings Volume 3882, (1999) https://doi.org/10.1117/12.361321

KEYWORDS: Etching, Interferometry, Gallium arsenide, Cameras, Semiconducting wafers, Process control, Dry etching, Control systems, Refractive index, Reflection

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Proceedings Article | 18 December 1998 Paper

Inductively coupled plasma etch of DUV MoSi photomasks: a designed study of etch chemistries and process results

Chris Constantine, David Johnson, Russell Westerman, Andrew Hourd

Proceedings Volume 3546, (1998) https://doi.org/10.1117/12.332879

KEYWORDS: Etching, Quartz, Plasma, Photomasks, Diffractive optical elements, Reactive ion etching, Plasma etching, Deep ultraviolet, Chemistry, Chromium

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Proceedings Article | 28 July 1997 Paper

Plasma etching of Cr photomasks: parametric comparisons of plasma sources and process conditions

Chris Constantine, David Johnson, Russell Westerman, Thomas Coleman, Thomas Faure

Proceedings Volume 3096, (1997) https://doi.org/10.1117/12.277267

KEYWORDS: Etching, Chromium, Critical dimension metrology, Oxygen, Diffractive optical elements, Plasma, Scanning electron microscopy, Plasma etching, Photoresist processing, Reactive ion etching

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As device design rules continue to shrink, on-mask Cr structures must experience a corresponding reduction in size. Although 0.25 micrometer design rules require only 1 micrometer Cr features, the use of OPC structures, which may be needed to minimize line foreshortening and corner rounding, necessitate features to be etched into the Cr which are significantly smaller than this. This need, coupled with the demand for reduced CD bias and improved CD uniformities, requires the use of an alternate chrome etch technology. Plasma etching of Cr can be highly anisotropic, greatly reducing the etch under cut which is responsible for the CD bias typically associated with wet etching. Reactive ion etching (RIE) can provide significant enhancements in the capability of replicating micron and sub-micron features, but the Cr etch rate non-uniformity which is typical of this technique can translate into a CD nonuniformity. This is due in part to the relatively high pressure of operation (50 - 100 mTorr which is necessary to reduce the self generated dc voltage And which minimizes the photo resist etch rate. Recently, high density plasma sources, such as inductively coupled plasma (ICP), have become available which have the ability to operate both at low pressures and high plasma density while maintaining a low and controllable dc voltage. The low pressure operation significantly improves the etch rate uniformity and consequently the CD uniformity. In this study a design of experiment (DOE) is used to investigate the parameter space associated with the dry etching of Cr using an ICP source. The responses of Cr etch rate, selectivity to photo resist, CD uniformity and mean CD to target are studied, and from this an optimized parameter space is defined. Within this space the effect of overetch, dc voltage and pattern loading on the CD uniformity are also investigated. The role played by the photo resist profile in determining the Cr etch profile is also studied and preliminary measurements are made to understand the effect of the above parameters on the mask CD bias.

Proceedings Article | 12 February 1997 Paper

Plasma etching of Cr photomasks: optimization of process conditions and CD control

Chris Constantine, David Johnson, Russell Westerman, Thomas Coleman, Thomas Faure, Leonard Dubuque

Proceedings Volume 3236, (1997) https://doi.org/10.1117/12.301179

KEYWORDS: Etching, Chromium, Critical dimension metrology, Plasma etching, Plasma, Oxygen, Scanning electron microscopy, Diffractive optical elements, Atomic force microscopy, Photoresist processing

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As device design rules continue to shrink, on-mask Cr structures must experience a corresponding reduction in size. Although 0.25 micrometer design rules require only 1 micrometer Cr features, the use of OPC structures, which may be needed to minimize line foreshortening and corner rounding, necessitate features to be etched into the Cr which are significantly smaller than this. This need, coupled with the demand for reduced CD bias and improved CD uniformities, requires the use of an alternate chrome etch technology. Plasma etching of Cr can be highly anisotropic, greatly reducing the etch undercut which is responsible for the CD bias typically associated with wet etching. Reactive ion etching (RIE) can provide significant enhancements in the capability of replicating micron and sub-micron features, but the Cr etch rate non-uniformity which is typical of this technique can translate into a CD non-uniformity. This is due in part to the relatively high pressure of operation (50 - 100 mTorr) which is necessary to reduce the self generated dc voltage and which, in turn, minimizes the photo resist etch rate. Recently, high density plasma sources, such as inductively coupled plasma (ICP), have become available which have the ability to operate both at low pressures and high plasma density while maintaining a low and controllable dc voltage. The low pressure operation significantly improves the etch rate uniformity and consequently the CD uniformity. By coupling this ICP plasma source with a non-contact backside photomask handling system and a true multi-station 'cluster tool.' In this study a design of experiment (DOE) is used to investigate the parameter space associated with the dry etching of Cr using an ICP source. The responses of Cr etch rate, selectivity to photo resist, CD uniformity and mean CD to target are studied, and from this an optimized parameter space is defined. Within this space the effect of overetch, dc voltage and pattern loading on the CD uniformity are also investigated. The role played by the photo resist profile in determining the Cr etch profile is also studied, and preliminary measurements are made to understand the effect of the above parameters on the mask CD bias.