Analysis of copper/fluoropolymer film systems for multilevel interconnects

Characteristics of film materials considered for multilevel interconnects -- Structure and dielectric properties of fluoropolymer films -- Properties of copper films -- Adhesion of metals to fluoropolymers -- Experimental methodology -- Fabrication of fluoropolymer films -- Fabrication of copper films -- Characterization of film materials -- Dielectric properties of fluoropolymer films -- Adhesion of copper to fluoropolymers

Neue Elektronische und Multifunktionale Polymerdünnschichten Ermöglicht durch die Initiierte Chemische Gasphasenabscheidung

The aim of this work was the establishment of initiated chemical vapor deposition (iCVD) at the Chair for Multicomponent Materials (Prof. Dr. Franz Faupel) and the development of iCVD thin film electrets for biomagnetic sensors. The iCVD process developed by Gleason et al. enables a high-precision film growth control and control of the resulting film functionality of the polymer thin films due to the CVD-typical growth characteristics and the solvent-free radical polymerization from the vapor phase. Based on the work of Gleason et al., the iCVD process is newly established and further developed as the first objective of this work at the Chair for Multicomponent Materials. In order to obtain a more detailed understanding of the underlying reaction processes and to improve the process control, an in-situ mass spectrometry extension for the iCVD process, which is newly developed in the course of this work, is also presented. Starting from simple insulators, which can currently be deposited by iCVD, the next objective is to investigate whether it is possible to produce so-called thin film electrets by iCVD. Electrets are functional dielectrics that can store a charge over a very long period of time and thus provide a (quasi)permanent electric field over a long period of time, much like a permanent magnet provides a magnetic field for a long period of time. Their versatile field of application ranges from electret microphones to energy generators and electrostatic air filters. Within the scope of this work, the electrets are intended for new electrostatic magnetic field sensors, which are developed in close cooperation with the Chair for Functional Nanomaterials (Prof. Dr. Rainer Adelung) as project A2 within the Collaborative Research Center (CRC) 1261. For this purpose, the long-standing experience in the field of thermal evaporation of Teflon AF thin film electrets at the Chair for Multicomponent is used and, among other things, it is investigated whether the iCVD fluoropolymers enable a further improvement of the charge carrier stability as well as better film control by the CVD-typical growth conditions. The subsequent objective is dedicated to the question of how iCVD electrets can be further developed and tailored for the application in sensors. This can only be achieved by a better understanding of the underlying charge storage mechanisms. Therefore, the influence of different end groups on the charge storage properties, enabled by the individual tunability of the film functionality in the iCVD process, is investigated first. In addition, new organic iCVD electret multilayers are demonstrated to specifically address challenges that may arise in connection with the electret component in sensors. Furthermore, an approach is demonstrated that allows the formation of microporous polymer films by phase separation during deposition, which can increase the effective surface charge. Finally, to complete the field, it is investigated whether it is possible to deposit conjugated thin films by iCVD via new acetylene-like monomers in contrast to the typical insulating iCVD films. Adhesion problems that occur during deposition, especially with fluoropolymer films, are finally solved by novel gradient copolymer films inspired by nature. The chemical composition of these films changes from polymer type A to polymer type B along the film thickness. With the help of the newly developed in-situ mass spectrometry extension, the deposition of the new nanoscale gradient copolymer films with film thicknesses below 30 nm is finally made possible. A combination of two materials in one material represents a completely new type of material in terms of physical and chemical properties. It not only enables improved adhesion, but can also pave new paths for organic electronics, future sub-wavelength devices and the replication of natural gradient structures, for example for molecular machines on the lower nanoscale

Tailoring the properties of PECVD deposited terpinen-4ol thin films

Polymer thin films have been of significant research interest in the field of, mechanics, optics, electronics and medicine. Bioactive coatings are extensively used in marine and medical field for the prevention of biofouling which is colonization of any wetted surface by flora and fauna. Fouling of the surfaces has severe implications for the performance of the material and biocide based coating have been used in the prevention of marine fouling. However, these coatings have adverse environmental effects. Natural antifouling products derived from organisms have been found to be an excellent alternative to biocide based strategies. Terpinen-4-ol derived from Australian Tea tree oil has antimicrobial properties. The Plasma enhanced chemical vapor deposition (PECVD) method has been used to develop environmentally friendly antifouling coating from Terpinen-4-ol. The effect of Process variables such as substrate temperature have been investigated on the PECVD of terpinen-4-ol. The influence of surface functionalization and the deposition mode of terpinen-4-ol plasma polymer on its antibacterial property has been studied. Coating created in the form of bilayer are tested for their marine antifouling behavior. The substrate temperature was found to influence the deposition mechanism of Terpinen-4-ol plasma polymers. Hydro Stable terpinen-4-ol plasma polymers were found to be formed at higher substrate temperature. Pulse plasma deposited films exhibited enhanced antibacterial performance. Grafting of ZnO nanoparticles onto the surface of the terpinen-4-ol polymer boosted the antibacterial and UV absorbing properties. The deposited bilayer coatings were effective in preventing the primary stage of marine biofouling. The bilayer acted as biocidal self-polishing coating

Surface and interfacial reactions involving inorganic and organic semiconductor substrates

Ph.DDOCTOR OF PHILOSOPH

Synthesis and fabrication of nanostructional functional polymeric materials via plasma processes and polymer modification

Ph.DDOCTOR OF PHILOSOPH

Improving tribomechanical properties of polymeric nanocomposite coatings

Low friction, high wear resistance and strong adhesion in polymeric coatings employed in a variety of industrial and domestic processes such as in ball bearings, water repellent surfaces, antiadhesive coatings, and anticorrosion systems are of significant interest for energy saving and durability purposes. Even small increases in friction can have implications on energy efficiency, life time expectancy and performance of such coatings

Nonthermal Plasma Technology as a Versatile Strategy for Polymeric Biomaterials Surface Modification: A Review

In modern technology, there is a constant need to solve very complex problems and to fine-tune existing solutions. This is definitely the case in modern medicine with emerging fields such as regenerative medicine and tissue engineering. The problems, which are studied in these fields, set very high demands on the applied materials. In most cases, it is impossible to find a single material that meets all demands such as biocompatibility, mechanical strength, biodegradability (if required), and promotion of cell-adhesion, proliferation, and differentiation. A common strategy to circumvent this problem is the application of composite materials, which combine the properties of the different constituents. Another possible strategy is to selectively modify the surface of a material using different modification techniques. In the past decade, the use of nonthermal plasmas for selective surface modification has been a rapidly growing research field. This will be the highlight of this review. In a first part of this paper, a general introduction in the field of surface engineering will be given. Thereafter, we will focus on plasma-based strategies for surface modification. The purpose of the present review is twofold. First, we wish to provide a tutorial-type review that allows a fast introduction for researchers into the field. Second, we aim to give a comprehensive overview of recent work on surface modification of polymeric biomaterials, with a focus on plasma-based strategies. Some recent trends will be exemplified. On the basis of this literature study, we will conclude with some future trends for research

Plasma Processing for Tailoring the Surface Properties of Polymers

This chapter details how plasma treatments can be used to tailor the wettability of polymers. A plasma is an excited gas, and exposure of a polymer to a plasma discharge generally results in an enhancement in surface energy and associated with this is an increase in wettability. The effect however can be short lived due to hydrophobic recovery. In this review the use of both low and atmospheric plasmas for the activation of polymers will be discussed, as will the use of these plasmas for the deposition of plasma polymerised coatings. The latter can be used to produce polymer surfaces with tailored functionalities, thus achieving stable water contact angles ranging from superhydrophilic to superhydrophobic, as required

Current Research in Thin Film Deposition

Today, thin films are near-ubiquitous and are utilised in a very wide range of industrially and scientifically important areas. These include familiar everyday instances such as anti-reflective coatings on ophthalmic lenses, smartphone optics, photovoltaics, decorative, and tool coatings. A range of somewhat more exotic applications also exists, such as astronomical instrumentation (e.g., ultra-low loss dielectric mirrors and beam splitters in gravitational wave detectors, such as laser interferometer gravitational-wave observatory (LIGO)), gas sensing, medical devices and implants, and accelerator coatings (e.g., coatings for the large hadron collider (LHC), and compact linear collider (CLIC) experiments at European organization for nuclear research (CERN)). This Special Issue will provide a platform for researchers working in any area within this highly diverse field to share and exchange their latest research findings. The Special Issue contains novel studies encompassing material characterisation techniques, a range of thin-film coating deposition processes and applications of such technology