Deliverables Study and development of screen printing light emitting polymer inks The study and development of a screen printable light emitting polymer ink have been performed during the project. The use of large-area screen printing of organic semiconductive films allows to produce light-emitting polymer devices with reproducible performance in a continuous process at low cost. The optimised procedure to realise the organic inks is divided in different steps: - Definition of the type and amount of solvents, the viscosity and the screen printing parameters to obtain right thickness and uniformity required for organic light emitting diodes; - Set up of the light emitting polymer inks fabrication procedure (solubilisation in solvents in temperature and controlled atmosphere) - Thickness and uniformity characterization after screen printing process. The light emitting polymer devices realised using these compositions showed good light emission efficiency, good thickness (65-80nm) good uniformity of light distribution. Plasma source geometry for high plasma density generation over the whole source area Plasma source geometry for high plasma density generation over the whole source area (1011 ions.cm-3 on 700 x 700 mm2): Generate inductively coupled plasma over large area required the careful design of a coil antenna to create uniform magnetic field. Plasma density measurements with 3 different coil geometries (2 loops, 2 serpentine coils and 3 loops connected in parallel) have shown clearly better results with the 3-loop coil. The corresponding ion current density is higher at the reactor periphery since it covers the whole magnetic pole area. Furthermore, the lead connection of the 3 antennas have been arranged outside the reactor, to keep the possibility to tune the plasma uniformity in balancing the power by tuning inductance. Nevertheless, the plasma profile presents a maximum at the reactor centre due to ambipolar diffusion. To decrease this effect, the magnetic pole located at the centre location have been removed in order to decrease the magnetic field i.e. to smooth the plasma profile. The results are the following: - Plasma uniformity with CHF3 gas: --Original configuration: over 70 x 70mm2=20 %; -- Removing 6 magnetic poles: 10%. Etching rate optimisation of SiO2: Etching experiments have been performed with the plasma source configuration described above. Etching experiments made with CF4 and CHF3 gases gave very good results in term of etching rate and etching uniformity. - SiO2 etching rate 70-100 nm/min - Uniformity over 600 x 600 mm2 :10% These performances are in the specifications. Introduction of screen printing technology in OLED displays by depositing conductive inks for pads and light emitting materials The development and use of large-area screen printing have been performed within this project to deposit inorganic conductive and organic semiconductive coatings and patterns to produce thin-film large-area light-emitting polymer devices with reproducible performance in a continuous process at low cost. The advatages using large-scale screen printing processes for light-emitting polymer for displays and information panels are in processing (environmentally friendly, continuous process), price (integration of components) and product features (design freedom, large-area, flexible devices). However, to enter these markets, development of large-scale fabrication technology is required, utilising the advantages of polymer processing. The technologies currently used are not directly suitable for large-scale production of most applications. Present deposition techniques include spin coating and dip coating for the deposition of the polymer layers and physical vapour deposition for the ultra-thin metal electrode. The advantages using the screen-printing technology for these purposes are: - Uncoupling of emitting device from electronics, improved connections between electrodes and electronic circuitry and higher raggedness and resistance to scratch. - Use high-resolution screen-printing which has been already used in other electronic related areas with deposition of layers very close per nature and thickness to those addressed in this project. - Large area screen-printing can bring a cost breakthrough in the polymeric area emitters, including for applications requiring various colours. Etching process with SiO2/Si selectivity for large area treatments Development of recipes for high selective etching: pressure, gas mixture, power, bias voltage. The Selectivity optimum with a gas mixture ratio C2H4/(CF4+C2H4) comprised between of 30% and 40%. with a RF power of 2000W and a pressure of 4 mTorr. Care must be taken on the cleanliness of the plasma chamber to guarantee the reproducibility of the results. Design of a large area MaPE ICP source and development of large area equipment Design of a large area MaPE ICP source: Topic of the development is to create a large area MaPE ICP source for integration in FHR in-line equipment for the application in dry etch and PECVD. Technological specification achieved: Type FHR MaPe ICPR 400 Size: 400mm x 190mm Flange: 495 mm x 235mm Working pressure: 2 x10-3 mbar - 2 x 10-1mbar Leakage rate: < 2x 10-9mbar l/s He RF- compatibility: 2MHz - 13,56MHz, ca 2,5KW integrated gas injection. The aim of this source is to find a principle solution for: - integration of the source in FHR in-line system (IN-LAN) - utilisation for dry etching and PECVD - utilisation in static and dynamic mode - possibility of upscaling in size for other equipment. Development of large area equipment: FHR is already producing in-line equipment for PVD processes. Based upon the innovative vertical in-line concept SV-InLan from FHR the MaPe ICP source technology was transferred to this innovative equipment concept with the following targets: - Utilisation for dry etching and PECVD processes; - Utilisation in static and dynamic mode; - Scaleability to larger or other dimensions. The SV InLan concept is modular and respecting the various requirement of modern thin film processing especially on flat substrates with utilisation in the following areas: - Flat panels in LCD, TFT and OLED technology; - Solar cells; - Mass production of electronic components like condenser, resistors, SAW filters etc; - Optical components like filters; - EMV shielding. The whole concept respects consequently in design of vacuum pumping, gas and production flow upscaling aspects of the equipment in terms of substrate size. Optimisation of operation frequency for high plasma density generation over the whole source area Generate inductively coupled plasma over large area required large antenna to coupled RF energy to the plasma. The main problem to solve is that long antenna with length comparable to the RF wavelength creates non-uniformity of power dissipation along the coil length (standing wave effect). This has been verified in our experiments made at 13.56MHz (RF wavelength 22m) with a 2 turn S-shaped antenna (17m) resulting in a non-uniformity of +200 %. The implemented solution consists in the use a set of coils in parallel connected to a 2 MHz generator. With this configuration, the plasma profile is symmetrical showing that the standing wave effect has been removed. Furthermore, the ion current density measurements versus the RF power shows clearly that the plasma density exhibits higher values at 2MHz (x 4) than at 13.56MHz Frequency. It is a direct consequence of a better coupling efficiency improved thanks to the higher pole magnetic permeability and the lower pole magnetic losses at 2MHz vs. 13.56MHz. The use of 2 MHz frequency with a set of antenna connected in parallel enables high plasma density generation (> 1011 ion. cm-3) over reactor large area. A dry etch process for polycrystalline silicon etch, silicon oxyde and Indium Tin Oxide (ITO). The fabrication of transistors with thin films of polycrystalline silicon uses thin films of silicon (typically near 100nm) covered by thicker silicon oxide films (typically between 100nm and 500nm). Also, it needs etch process with high selectivity between silicon oxide and silicon. Such process could increase significantly the throughputs of microelectronic fabrication on glass substrate. Furthermore, the loading effect could be significantly decreased with such process. Fluorocarbon process are currently used for silicon and silicon oxide etch. It is well known that the selectivity could be increased by increasing the carbon content in the gas mixture. It also depending of the degree of dissociation of fluorocarbon. Using gas mixture as CF4 with CH4 or C2H4 in an ICP-RIE reactor makes possible such process. While dry etch of silicon and silicon oxide are currently used for microelectronics on glass substrate, the Indium Tin Oxide used for the pixel electrode is wet etched. Also dry etch process on ITO can be realized by using CH4 with argon and H2. Besides, the fabrication of a large scale ICP reactor where such process has been transferred is an opportunity for the microelectronic on large scale glass substrate. Fabrication of Thin Film Transistors (TFT) based on Low Temperature Polycrystalline Silicon (LTPS) for active matrix for liquid crystal The fabrication of Thin Film Transistors (TFT) based on Low Temperature Polycrystalline silicon (LTPS) is commonly used for the fabrication of AMLCD. Because of the stability of their threshold voltage, polycrystalline silicon active layer TFT could be a solution to increase the reliability of Liquid Crystal Display for THALES avionic applications. Moreover, it allows high electronic mobility compatible with displays drivers and complex electronic functions integration on glass. Besides, such TFT could be used to fabricate Active matrix in order to drive organic diode. Indeed, Organic Light Emission display seems to be an interesting technology for the future market of flat panels. Due to their current driving system, an active driving system of the organic diode needs TFT with good stability in saturated regime only allowed today with the polycrystalline silicon TFT technology. A list of test for the characterization of patterned ITO substrates for organic light emitting diodes technology The processed plates with structured ITO and glass used in OLED technology are characterized using a list of tests to analyse the improvements of performances. The list of test required for the complete characterisation is:v Optical and emission (UV-Vis, PL and EL spectra and viewing angle)v Electro-optical. The measurements are controlled by a LabView software: the basic functions are the timing and control of driving voltage, luminance and current readings and screening of curves.v Surface and morphology measurements. AFM analysis is used to check the uniformity and the roughness of ITO and glass structured by plasma etching.v Lifetime and shelflife. The photo-oxidation experiments are carried out by periodically measuring the UV-Vis spectra. The chemical degradation of the light emitting materials is controlled by IR measurements. The coupling between OLED and diffractive optics has been realized by photolitography and etching processes. Different diffractive gratings were realised on glass surface: - steps 4-50 micron- relieves height 200-650nm. The efficiency increases decreasing the step of the grating more than 30% for 4-6 micron. Sub-structured anode with diffractive gratings (12 micron) were realized on ITO layer: the increasing of efficiency due to sub-structuring of ITO is about 15%. Development and characterisation of conductive screen printing pastes for ITO patterned glass and plastic substrates The development and characterisation of screen printing inks have been performed in order to test the mechanical and electrical properties of conductive compositions to generate patterned contacts and electronics in light emitting polymer displays on ITO glass and plastic substrates. The advantages using the screen printing technology for these purposes are: uncoupling of emitting device from electronics, improved connections between electrodes and electronic circuitry and higher raggedness and resistance to scratch. The typical components of a paste to be right selected are: functional phase (Au, Pt/Au, Ag, Pd/Ag, Cu and Ni), binder (glass, a crystalline oxide) and vehicle (solvents).The development of an ink formulation includes: - Preliminary selection of metal powders and binders (morphological shape, particle size distributions); - Mix of two kinds of powders to produce samples with different relative concentration of binder; - Selection of the organic carrier and its concentration to reach inks with proper viscosity; - Studying inks' rheologic and pseudoplastic behaviours. The characterisation of the mechanical and electrical properties is performed after the screen printing, drying and firing of these compositions to obtain the desired electrical and mechanical properties. Welding technology for a large area etching electrode consisting of aluminium The electrode body consists of massive Aluminium with integrated cooling channels. Requirements for leak tightness and warpness of surface led to decision that necessary performance / reliability can be performed only by welding. At project begin no experience in welding Aluminium components in this mechanical dimension was available. Detailed investigations were made especially to the welding process and design rules for preparation of the components before welding and the aspect of final mechanical treatment. The results of this investigation enable FHR to produce vacuum components of Aluminium for applications in the field of etching, PVD and CVD. Design of a large area etching electrode with uniform temperature distribution Topic of the development is to create a large area electrode for plasma etching processes with useable area of 850mm x 850mm. Technological specification achieved: High temperature uniformity of +/- 5°C Working Temperature: 20 - 60° Working pressure: 2 x10-3 mbar 3 x 10-1mbar Leakage rate: < 2x 10-9mbar l/s He Warpness: < 0,2 mm RF- compatibility : 2 MHz - 13,56 MHz RF dark space shielding. High adjustability with central lift from 50 - 100mm. Request for temperature uniformity, process compatibility resulted in design of the electrode body of Aluminium. A hard Anox surface protects the surface from process gases and gives necessary mechanical resistance. The temperature uniformity will be granted by a thermostat with high flow of > 10l/min of cooling media. Due to good corrosion resistance and electrical insulation und rf field a dielectric Silicon coolant fluid Baysilone KT3 (Bayer) is applied. Design of dark space shielding grants wide working range in terms of applicable pressure. The electrode is a first industrial prototype of large area etching electrode and important part of the ICP setup. Within the project the final aim is to create a complete industrial prototype of an ICP etching assembly applicable for in-line or batch equipment. A redesign was performed after finalising all process tests and having test results available. Searching for OpenAIRE data... There was an error trying to search data from OpenAIRE No results available
