Chemical vapor deposition (CVD) polymerization utilizes the delivery of vapor-phase monomers to form chemically well-defined polymeric films directly on the surface of a substrate. CVD polymers are desirable as conformal surface modification layers exhibiting strong retention of organic functional groups, and, in some cases, are responsive to external stimuli. Traditional wet-chemical chain- and step-growth mechanisms guide the development of new heterogeneous CVD polymerization techniques. Commonality with inorganic CVD methods facilitates the fabrication of hybrid devices. CVD polymers bridge microfabrication technology with chemical, biological, and nanoparticle systems and assembly. Robust interfaces can be achieved through covalent grafting enabling high-resolution (60 nm) patterning, even on flexible substrates. Utilizing only low-energy input to drive selective chemistry, modest vacuum, and room-temperature substrates, CVD polymerization is compatible with thermally sensitive substrates, such as paper, textiles, and plastics. CVD methods are particularly valuable for insoluble and infusible films, including fluoropolymers, electrically conductive polymers, and controllably crosslinked networks and for the potential to reduce environmental, health, and safety impacts associated with solvents. Quantitative models aid the development of large-area and roll-to-roll CVD polymer reactors. Relevant background, fundamental principles, and selected applications are reviewed.

Vapor based polymer deposition methods have evolved to address the limitations of solution polymerization. However this field of vapor based polymerization suffers from varied nomenclature and would benefit from a review article that brought together the different approaches to vapor based polymerization with an effort to present existing nomenclature, clearly identify the various approaches within this field and summarize recent results. This review article is written with the purpose of compiling recent advances in vapor based deposition methods of polymers with a focus on applications that will continue to drive research in this field. We hope that this article encourages researchers engineering novel polymer applications to give vapor based polymerization a serious consideration apart from solution polymerization methods.

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ISR develops, applies and teaches advanced methodologies of design and analysis to solve complex, hierarchical,heterogeneous and dynamic problems of engineering technology and systems for industry and government.

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.