Multi-level analysis of atomic layer deposition barrier coatings on additively manufactured plastics for high vacuum applications

While hardware innovations in micro/nano electronics and photonics are heavily patented, the rise of the open-source movement has significantly shifted focus to the importance of obtaining low-cost, functional and easily modifiable research equipment. This thesis provides a foundation of open source development of equipment to aid in the micro/nano electronics and photonics fields. First, the massive acceptance of the open source Arduino microcontroller has aided in the development of control systems with a wide variety of uses. Here it is used for the development of an open-source dual axis gimbal system. This system is used to characterize optoelectronic properties of thin transparent films at varying angles. Conventionally, the ubiquity of vacuum systems in semiconductor fabrication has precluded the development of an open-source development in the “fab” environment and thus has high foundational and operational costs. In order to make vacuum systems and their components cost-effective in a research environment there has been a paradigm shift towards refurbishing and repairing instead of replacing legacy systems. These legacy systems are built, and operate on the principle that the vacuum industry is a small industry, and hence only a small number of sizes and types of parts may be used to reduce costs. The assumption that the vacuum industry is a small industry is no longer valid. The semiconductor industry alone, which is a subset of the vacuum industry, was worth over USD 481b and increasing. Hence,there is a need to not only introduce new methods but also new materials that make up these systems. Additive manufacturing is a low-waste, low-capital cost way to make custom equipment. The most popular materials used in additive manufacturing processes are polymer blends. 3-D printing using Fused Filament Fabrication (FFF) methods has been used to create custom objects for laboratories. However, the use of polymer-based materials is conspicuously absent in the development of vacuum systems, especially those that are used for semiconductor fabrication. There are two major problems identified when polymeric materials are used to make vacuum systems: finding a way to prevent outgassing (which can subsequently lead to contamination), and sealing them so that they can hold a vacuum. This work has demonstrated how an inorganic barrier layer introduced via Atomic Layer Deposition (ALD) can alleviate outgassing to a large extent under high vacuum levels (1E-6 to 1E-7 torr). Recognizing the importance of ALD alumina in back end of the line (BEOL) semiconductor processing, films were deposited on 3-D printed polymer-based substrates with differing constituents. These samples were tested in a bespoke gas analysis chamber for outgassing characterization. Surface and bulk characterization was completed using various tools such as scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDX), x-ray photoelectron spectroscopy (XPS), attenuated total reflectance - Fourier transform infrared spectroscopy (ATR-FTIR) and others. Additionally, spectroscopic ellipsometry (SE) was used to understand how the concept of thickness of a film deposited on a porous polymer-based sample does not correlate directly with its conventional definition. Also, an effort is made to understand the mechanism of ALD alumina deposition on porous plastic surfaces.It was concluded that this deposition is a complex amalgamation of physical and chemical properties of both the polymer and the precursor gases. Finally, recommendations are made for AM materials to be used in vacuum systems

MilkGuard: Low-Cost, Polymer-based Sensor for the Detection of Escherichia coli in Donated Human Breast Milk

Breast milk, the gold standard for infant nutrition, could prevent up to 13% of child deaths worldwide. However, many mothers are unable to breastfeed due to health conditions and other factors. Because of this, a network of more than 500+ human milk banks, which collect and distribute donated breast milk to infants, have emerged worldwide. However, operational costs to ensure the safety of this milk remain time-intensive and costly. There are no existing diagnostics for rapid and on-site detection of bacterial contaminants in donated milk. Currently, many milk banks send samples to outside laboratories for bacterial culturing tests, which take 24-48 hours to receive results. In contrast, MilkGuard is an on-site detection method which ensures results in hours rather than days. To determine whether or not E.coli is present in donated milk, a drop of milk is deposited onto the sensor. If the milk is contaminated, the sensor will turn a blue color due to an enzyme-substrate reaction of the bacteria. The goal of the project is to create a cost and rapid alternative to traditional bacterial culturing testing to screen for E. coli bacteria in donated human breast milk. This will allow users to ensure that milk samples are sterile enough to provide to young infants, while also providing breast milk banks an alternative that will allow them to screen more samples in a shorter amount of time

A Digital Manufacturing Process For Three-Dimensional Electronics

Additive manufacturing (AM) offers the ability to produce devices with a degree of three-dimensional complexity and mass customisation previously unachievable with subtractive and formative approaches. These benefits have not transitioned into the production of commercial electronics that still rely on planar, template-driven manufacturing, which prevents them from being tailored to the end user or exploiting conformal circuitry for miniaturisation. Research into the AM fabrication of 3D electronics has been demonstrated; however, because of material restrictions, the durability and electrical conductivity of such devices was often limited. This thesis presents a novel manufacturing approach that hybridises the AM of polyetherimide (PEI) with chemical modification and selective light-based synthesis of silver nanoparticles to produce 3D electronic systems. The resulting nanoparticles act as a seed site for the electroless deposition of copper. The use of high-performance materials for both the conductive and dielectric elements created devices with the performance required for real-world applications. For printing PEI, a low-cost fused filament fabrication (FFF); also known as fused deposition modelling (FDM), printer with a unique inverted design was developed. The orientation of the printer traps hot air within a heated build environment that is open on its underside allowing the print head to deposit the polymer while keeping the sensitive components outside. The maximum achievable temperature was 120 °C and was found to reduce the degree of warping and the ultimate tensile strength of printed parts. The dimensional accuracy was, on average, within 0.05 mm of a benchmark printer and fine control over the layer thickness led to the discovery of flexible substrates that can be directly integrated into rigid parts. Chemical modification of the printed PEI was used to embed ionic silver into the polymer chain, sensitising it to patterning with a 405 nm laser. The rig used for patterning was a re-purposed vat-photopolymerisation printer that uses a galvanometer to guide the beam that is focused to a spot size of 155 µm at the focal plane. The positioning of the laser spot was controlled with an open-sourced version of the printers slicing software. The optimal laser patterning parameters were experimentally validated and a link between area-related energy density and the quality of the copper deposition was found. In tests where samples were exposed to more than 2.55 J/cm^2, degradation of the polymer was experienced which produced blistering and delamination of the copper. Less than 2.34 J/cm^2 also had negative effect and resulted in incomplete coverage of the patterned area. The minimum feature resolution produced by the patterning setup was 301 µm; however, tests with a photomask demonstrated features an order of magnitude smaller. The non-contact approach was also used to produce conformal patterns over sloped and curved surfaces. Characterisation of the copper deposits found an average thickness of 559 nm and a conductivity of 3.81 × 107 S/m. Tape peel and bend fatigue testing showed that the copper was ductile and adhered well to the PEI, with flexible electronic samples demonstrating over 50,000 cycles at a minimum bend radius of 6.59 mm without failure. Additionally, the PEI and copper combination was shown to survive a solder reflow with peak temperatures of 249°C. Using a robotic pick and place system a test board was automatically populated with surface mount components as small as 0201 resistors which were affixed using high-temperature, Type-V Tin-Silver-Copper solder paste. Finally, to prove the process a range of functional demonstrators were built and evaluated. These included a functional timer circuit, inductive wireless power coils compatible with two existing standards, a cylindrical RF antenna capable of operating at several frequencies below 10 GHz, flexible positional sensors, and multi-mode shape memory alloy actuators

An Analysis of the factors influencing paper selection for books of reproduced fine art

Toner-based digital presses are now capable of matching offset lithographic presses in image and print quality. Current trends show increased interest in printing fine art books on digital presses. It is necessary to understand the extent to which digital printing systems are capable of accurately rendering fine-art reproductions. This research analyzed paper properties that maximize image quality and preference for digitally printed fine art reproductions. Four images, representing four art media, were printed on twelve papers using two digital presses. The twelve papers represented different combinations of color, print-show-through, roughness and gloss. A psychophysical experiment was conducted in which observers ranked the twelve papers for each image on the basis of image quality, color rendering quality, and surface appearance quality. The results were analyzed and a model was developed to predict the probability that a paper was ranked in the top three. Paper color (coolness), basis weight, roughness, and gloss were model parameters. Unlike gloss, roughness, and print-show-through, there was no previous metric for quantifying coolness. Therefore, an additional experiment was conducted to develop a model to predict the perception of coolness using colorimetry. An alternative experiment model was also developed that included parameters such as caliper, print gloss, line raggedness, and dot circularity. The resulting models allowed for the optimization of paper parameters that maximize the probability a paper will produce preferred and high quality images. It was concluded that the probability a book was judged as having high image quality was optimized for papers with high coolness, low roughness and low gloss. Neither print show-through, line raggedness, nor mottle were significant factors. An additional lexical analysis was performed for observer descriptions of their ranking behavior. This analysis provided complementary data to the psychophysical results. Observers\u27 descriptions of their ranking strategies did not match the rank data, suggesting a possible disconnect between observers\u27 conscious and subconscious ranking behaviors

Liquid Metal Printing with Scanning Probe Lithography for Printed Electronics

In den letzten Jahren hat das „Internet der Dinge“ (Englisch Internet of Things, abgekürzt IoT), das auch als Internet of Everything (Deutsch frei „Internet von Allem“) bezeichnet wird, mit dem Aufkommen der „Industrie 4.0“ einen Strom innovativer und intelligenter sensorgestützter Elektronik der neuen Generation in den Alltag gebracht. Dies erfordert auch die Herstellung einer riesigen Anzahl von elektronischen Bauteilen, einschließlich Sensoren, Aktoren und anderen Komponenten. Gleichzeitig ist die herkömmliche Elektronikfertigung zu einem hochkomplexen und investitionsintensiven Prozess geworden. In dem Maße, wie die Zahl der elektronischen Bauteile und die Nachfrage nach neuen, fortschrittlicheren elektronischen Bauteilen zunimmt, steigt auch die Notwendigkeit, effizientere und nachhaltigere Wege zur Herstellung dieser Bauteile zu finden. Die gedruckte Elektronik ist ein wachsender Markt, der diese Nachfrage befriedigen und die Zukunft der Herstellung von elektronischen Geräten neu gestalten könnte. Sie erlaubt eine einfache und kostengünstige Produktion und ermöglicht die Herstellung von Geräten auf Papier- oder Kunststoffsubstraten. Für die Herstellung gibt es dabei eine Vielzahl von Methoden. Techniken auf der Grundlage der Rastersondenlithografie waren dabei schon immer Teil der gedruckten Elektronik und haben zu Innovationen in diesem Bereich geführt. Obwohl die Technologie noch jung ist und der derzeitige Stand der gedruckten Elektronik im industriellen Maßstab, wie z. B. die Herstellung kompletter integrierter Schaltkreise, stark limitiert ist, sind die potenziellen Anwendungen enorm. Im Mittelpunkt der Entwicklung gedruckter elektronischer Schaltungen steht der Druck leitfähiger und anderer funktionaler Materialien. Die meisten der derzeit verfügbaren Arbeiten haben sich dabei auf die Verwendung von Tinten auf Nanopartikelbasis konzentriert. Die Herstellungsschritte auf der Grundlage von Tinten auf Nanopartikelbasis sind komplizierte Prozesse, da sie das Ausglühen (Englisch Annealing) und weitere Nachbearbeitungsschritte umfassen, um die gedruckten Muster leitfähig zu machen. Die Verwendung von Gallium-basierten, bei/nahe Raumtemperatur flüssigen Metallen und deren direktes Schreiben für vollständig gedruckte Elektronik ist immer noch ungewöhnlich, da die Kombination aus dem Vorhandensein einer Oxidschicht, hohen Oberflächenspannungen und Viskosität ihre Handhabung erschwert. Zu diesem Zweck zielt diese Arbeit darauf ab, Methoden zum Drucken von Materialien, einschließlich Flüssigmetallen, zu entwickeln, die mit den verfügbaren Druckmethoden nicht oder nur schwer gedruckt werden können und diese Methoden zur Herstellung vollständig gedruckter elektronischer Bauteile zu verwenden. Weiter werden Lösungen für Probleme während des Druckprozesses untersucht, wie z. B. die Haftung der Tinte auf dem Substrat und andere abscheidungsrelevante Aspekte. Es wird auch versucht, wissenschaftliche Fragen zur Stabilität von gedruckten elektronischen Bauelementen auf Flüssigmetallbasis zu beantworten. Im Rahmen der vorliegenden Arbeit wurde eine auf Glaskapillaren basierenden Direktschreibmethode für das Drucken von Flüssigmetallen, hier Galinstan, entwickelt. Die Methode wurde auf zwei unterschiedlichen Wegen implementiert: Einmal in einer „Hochleistungsversion“, basierend auf einem angepassten Nanolithographiegerät, aber ebenfalls in einer hochflexiblen, auf Mikromanipulatoren basierenden Version. Dieser Aufbau erlaubt einen on-the-fly („im Fluge“) kapillarbasierten Druck auf einer breiten Palette von Geometrien, wie am Beispiel von vertikalen, vertieften Oberflächen sowie gestapelten 3D-Gerüsten als schwer zugängliche Oberflächen gezeigt wird. Die Arbeit erkundet den potenziellen Einsatz dieser Methode für die Herstellung von vollständig gedruckten durch Flüssigmetall ermöglichten Bauteilen, einschließlich Widerständen, Mikroheizer, p-n-Dioden und Feldeffekttransistoren. Alle diese elektronischen Bauelemente werden ausführlich charakterisiert. Die hergestellten Mikroheizerstrukturen werden für temperaturgeschaltete Mikroventile eingesetzt, um den Flüssigkeitsstrom in einem Mikrokanal zu kontrollieren. Diese Demonstration und die einfache Herstellung zeigt, dass das Konzept auch auf andere Anwendungen, wie z.B. die bedarfsgerechte Herstellung von Mikroheizern für in-situ Rasterelektronenmikroskop-Experimente, ausgeweitet werden kann. Darüber hinaus zeigt diese Arbeit, wie PMMA-Verkapselung als effektive Barriere gegen Sauerstoff und Feuchtigkeit fungiert und zusätzlich als brauchbarer mechanischer Schutz der auf Flüssigmetall basierenden gedruckten elektronischen Bauteile wirken kann. Insgesamt zeigen der alleinstehende, integrierte Herstellungsablauf und die Funktionalität der Geräte, dass das Potenzial des Flüssigmetall-Drucks in der gedruckten Elektronik viel größer ist als einzig die Verwendung zur Verbindung konventioneller elektronischer Bauteile. Neben der Entwicklung von Druckverfahren und der Herstellung elektronischer Bauteile befasst sich die Arbeit auch mit der Korrosion und der zusätzlichen Legierung von konventionellen Metallelektroden in Kontakt mit Flüssigmetallen, welche die Stabilität der Bauteil beinträchtigen könnten. Zu diesem Zweck wurde eine korrelierte Materialinteraktionsstudie von gedruckten Galinstan- und Goldelektroden durchgeführt. Durch die kombinierte Anwendung von optischer Mikroskopie, vertikaler Rasterinterferometrie, Rasterelektronenmikroskopie, Röntgenphotonenspektroskopie und Rasterkraftmikroskopie konnte der Ausbreitungsprozess von Flüssigmetalllinien auf Goldfilmen eingehend charakterisiert werden. Diese Studie zeigt eine unterschiedliche Ausbreitung der verschiedenen Komponenten des Flüssigmetalls sowie die Bildung von intermetallischen Nanostrukturen auf der umgebenden Goldfilmoberfläche. Auf der Grundlage der erhaltenen zeitabhängigen, korrelierten Charakterisierungsergebnisse wird ein Modell für den Ausbreitungsprozess vorgeschlagen, das auf dem Eindringen des Flüssigmetalls in den Goldfilm basiert. Um eine ergänzende Perspektive auf die interne Nanostruktur zu erhalten, wurde die Röntgen-Nanotomographie eingesetzt, um die Verteilung von Gold, Galinstan und intermetallischen Phasen in einem in das Flüssigmetall getauchten Golddraht zu untersuchen. Schlussendlich werden Langzeitmessungen des Widerstands an Flüssigmetallleitungen, die Goldelektroden verbinden, durchgeführt, was dazu beiträgt, die Auswirkungen von Materialwechselwirkungen auf elektronische Anwendungen zu bewerten

An Analysis of the art image interchange cycle within fine art museums

The art image interchange cycle is the procedure carried out by fine art museums in reproducing fine artwork --starting with the imaging of the original work, then digital processing, and lastly, repurposing for output to achieve a high-quality replica in a range of possible media. There are many areas of importance within this process, such as digital image processing, standardization, test targets use, and color management. This research has sought to analyze the fine art image interchange through understanding the background areas and how they apply, as well as benchmarking what museums are already doing with the intention of improving and standardizing the process. Upon completion of an adequate background study of the literature (concentrated on color management theory, test targets use, and fine art reproduction) this research focused on four main areas. First, a review of international standards was established and how they can be used to benefit museums. Second, a review of test targets was conducted and how best they can be implemented in fine art reproduction. Third, a number of museum workflows were benchmarked and documented - a workflow experiment was created and implemented for documentation purposes (and future image quality analysis). Lastly, a case study was conducted of a local fine art museum\u27s process of creating a fine art catalog, to better understand an average museum\u27s fine art image interchange. The research concluded that the practice of standardization could be improved within museums. As far as test targets, there was a large range of understanding and use. The benchmarking of three museums was completed, and it was determined that the process of documenting workflow was a difficult task to have implemented. Lastly, in x the case study, much was gained through the interviews, placing a great importance on communication, planning, and standardization

Modeling and Halftoning for Multichannel Printers: A Spectral Approach

Printing has been has been the major communication medium for many centuries. In the last twenty years, multichannel printing has brought new opportunities and challenges. Beside of extended colour gamut of the multichannel printer, the opportunity was presented to use a multichannel printer for ‘spectral printing’. The aim of spectral printing is typically the same as for colour printing; that is, to match input signal with printing specific ink combinations. In order to control printers so that the combination or mixture of inks results in specific colour or spectra requires a spectral reflectance printer model that estimates reflectance spectra from nominal dot coverage. The printer models have one of the key roles in accurate communication of colour to the printed media. Accordingly, this has been one of the most active research areas in printing. The research direction was toward improvement of the model accuracy, model simplicity and toward minimal resources used by the model in terms of computational power and usage of material. The contribution of the work included in the thesis is also directed toward improvement of the printer models but for the multichannel printing. The thesis is focused primarily on improving existing spectral printer models and developing a new model. In addition, the aim was to develop and implement a multichannel halftoning method which should provide with high image quality. Therefore, the research goals of the thesis were: maximal accuracy of printer models, optimal resource usage and maximal image quality of halftoning and whole spectral reproduction system. Maximal colour accuracy of a model but with the least resources used is achieved by optimizing printer model calibration process. First, estimation of the physical and optical dot gain is performed with newly proposed method and model. Second, a custom training target is estimated using the proposed new method. These two proposed methods and one proposed model were at the same time the means of optimal resource usage, both in computational time and material. The third goal was satisfied with newly proposed halftoning method for multichannel printing. This method also satisfies the goal of optimal computational time but with maintaining high image quality. When applied in spectral reproduction workflow, this halftoning reduces noise induced in an inversion of the printer model. Finally, a case study was conducted on the practical use of multichannel printers and spectral reproduction workflow. In addition to a gamut comparison in colour space, it is shown that otherwise limited reach of spectral printing could potentially be used to simulate spectra and colour of textile fabrics

The Effect of Optical Brightening Agent (OBA) in Paper and Illumination Intensity on Perceptibility of Printed Colors

Widely utilized sanctioned color aims for commercial printing are based on paper substrates without optical brightening agents, also known as OBAs. However, in today\u27s market, more and more paper is manufactured with OBAs. This could be problematic for commercial printers as OBAs influence not only paper conformity, but also the accuracy printed colors. This can lead to color mismatch between proofs and the final prints. Recognizing this condition, the objectives of this research were two-fold: first, to verify the perceived color difference between prints due to the presence of OBAs, and second, to study the perceptibility of color differences caused by OBAs in paper substrates, combined with quantitative measurement assessment. In order to satisfy these objectives, the following research questions were investigated: Does CIEDE 2000(∆E00) correlate better with visual scaling or ranking for color differences of printed color pairs than CIELABDE (∆E*ab)? Do different illuminant intensity levels (ISO 3664 P1: 2000lx and P2: 500lx) affect human perceptibility of color differences for color pairs with dark shades? A psychophysical experiment was carried out for evaluating color differences using printed color patches. In total, 27 pairs of printed color patches derived from the IT8.7/4 Target (1,617 color patches) were prepared using the same colorants printed on paper with and without OBA. Each pair was assessed at two levels of illumination by a panel of thirty-four observers. The visual results were used to investigate the relationship between color difference metrics and visual scaling (ranking) of color differences induced by OBAs, as well as the relationship between illumination intensity level and visual scaling of color samples with high-density. The results indicated that: (a) There is better correlation between ∆E00 and the visual scaling of OBA-induced color differences than ∆E*ab; and (b) there is no association between different illumination intensities (i.e., ISO: 3664 P1, P2) and visual scaling of color differences in high-density areas

The Adoption of Next Generation Digital Printing Technology in Package Printing

This research addresses the question of which packaging market segments are best suited to adopt next generation digital printing technology in the near future. According to McCluskey and Larson (2001), Molly (2005), and Eldred (2008), waste reduction and cost effectiveness in short run printing, short leadtime printing, and custom printing are the primary benefits of digital printing. The researcher screened eight major package market segments to determine which segments had the most need for these benefits. At the conclusion of this effort, the researcher identified flexible packaging and folding cartons as the two strongest candidates for early penetration by next generation digital printing technologies. The researcher then analyzed each of these markets in detail. An assessment of technology readiness led the researcher to focus on the folding carton market. Data gathered from folding carton converter interviews indicated that jobs with run lengths less than 12,000 B1 sheets are poorly suited for offset presses and constitute short runs. Jobs less than 2,000 B1 sheets are typically uneconomic to produce. Based on job cost models developed for this research, runs up to 2,000 B1 sheets can be economically produced by the HP 30000, and runs in excess of 12,000 B1 sheets can be economically produced by the Landa S10 in the long term. The other benefits of digital printing, short lead time printing and customization, could potentially be used to create on-package promotions targeted to narrow local markets. To assess this opportunity, the researcher surveyed 4,562 SKUs in Walmart, Wegmans, and PriceRite, and found that folding cartons with on-package promotions constituted five to fifteen percent of all folding cartons observed. During the interview phase of the research, the researcher found that existing distribution chains in the US are poorly adapted to delivering localized promotions to specific stores. Nevertheless, one converter stated some large brands were asking for localized promotions, so the opportunity may be real. Thus, the researcher concluded that the folding carton market is best suited to adopt next generation digital printing technology in the near future

Synthesis and Drop-on-Demand Deposition of Graphene Derivative Inks for Flexible Thin Film Electronics

This dissertation presents methods for deposition and post-processing of Graphene-Carboxymethyl Cellulose (G-CMC) and Graphene Oxide (GO) aqueous functional inks using a custom drop-on-demand (DOD) printer to fabricate mechanically flexible, non-transparent and transparent thin film electronic devices. Thin films on flexible substrates find use in lightweight, low profile, and conformable electronic devices. Such devices can include chemical sensors, flexible RFID tags, bioelectronics circuits, lightweight electronics for space systems, and transparent electrodes for optoelectronic systems. The goal of this research project is to provide simple methods for fabrication of these devices using environmentally friendly and easy to synthesize functional inks. Therefore, two graphene based inks are utilized; GO and a novel Carboxymethyl Cellulose (CMC) functionalized aqueous dispersion of Graphene, G-CMC. Proposed functional inks are deposited on treated substrates by DOD printing. Deposited thin films were post-processed by use of a muffle furnace or a pulsed laser system. Furthermore, gold doped G-CMC films and G-Silver Nanoprism (G-AgNP) composite inks were developed to enhance film electrical properties. Inkjet printed films on glass substrates were characterized in terms of their electrical, optical, and mechanical properties. Correlations between film thickness, optical transmittance, and conductivity were investigated. It was possible to deposit homogeneous thin films at 100 nm to 2000 nm thickness. G-CMC films exhibited good scaling of conductance where thicker films had ~ 660 Ω/sq sheet resistance. Gold doped and G-AgNP composite semi-transparent films exhibited enhanced conductance with sheet resistances of ~ 700 Ω/sq at 35% transparency and ~ 374 Ω/sq at 50% transparency, respectively. Laser assisted treatment of samples was conducted to investigate two opportunities; pulsed laser thermal treatment and pulsed laser micromachining on rigid and flexible substrates. Effect of laser parameters was investigated to establish guidelines for thin film thermal treatment and micromachining Finally, novel flexible sensors and circuits were fabricated to demonstrate task driven performance of proposed materials and methods. Based on the presented work, proposed methods and functional inks show promise for fabricating simple electronic devices on flexible and rigid substrates. It is believed that presented advances may benefit industrial fields that require scalable and simple thin film fabrication methods