AVS1997 Session PS+FP-MoA: Flat Panel Plasma Sources & Processes

Monday, October 20, 1997 2:00 PM in Room A5/6

Monday Afternoon

Start	Invited?	Item
2:00 PM	Invited	PS+FP-MoA-1 The Dynamics and Some Fundamental Research Problems Associated with Monochrome and Color Plasma Display Panels W. Williamson, Jr. (Embry-Riddle Aeronautical University); A.D. Compaan, C.E. Theodosiou, A. Shvydky, J.R. Gottschalk, J.M. Truxon, S. Ambalanath (The University of Toledo) In many respects the display industry may be considered to be a mature industry, however, in the near future alternatives to CRT's and LCD's will be entering the marketplace in volume. One type of alternative display device is the plasma display panel (pdp). A short discussion of the physical processes involved in pdp discharges will be presented. This will be followed by a more detailed account of a 1-D model of a helium filled ac discharge in a pdp. Comparisons between theoretical models and experimental measurements of current pulses and time-resolved optical emissions will be discussed. Some fundamental physical problems associated with the continued development of brighter, higher resolution color panels will be summarized. Supported in part by NSF-ECS-9615237
2:40 PM		PS+FP-MoA-3 Analysis of the Discharge Mechanism of He-Ne-Xe Gas Mixture in a Surface Type AC PDP J.H. Seo, H.S. Jeong, J.K. Kim, K.S. Moon, J.H. Yang, K.W. Whang (Seoul National University, Korea) He-Ne-Xe gas mixture is widely used in AC plasma display panels due to their good discharge characteristics such as the high luminance, luminance efficiency, good color purity and low driving voltage. Until now, however, their discharge mechanisms are merely understood. In this work, a plasma chemistry model for He-Ne-Xe mixture is established to understand the discharge mechanism. Comprehensive energy levels of helium, neon, and xenon, electron impact and heavy particle reactions are included in the model. The plasma chemistry model is solved with 2-dimensional multi-fluid AC PDP simulation code. A Boltzmann code is used to obtain the electron energy distribution function and electron impact rate constants. The discharge pathway in the He-Ne-Xe mixture in a surface type AC PDP has been identified and this understanding will be elaborated in conjunction with the improvement of luminance,efficiency and color purity.
3:00 PM		PS+FP-MoA-4 Discharge Characteristics of Various DC-PDP Cell Structures B.J. Shin, H.S. Jeong, J.H. Seo, W.J. Jeong, K.W. Whang (Seoul National University, Korea) The various DC-PDP cell structures including a planar electrode, a wall-electrode, and surface discharge electrode have been suggested and compared with the discharge characteristics of each cell structures. The wall-cathode has a sufficient discharge electrode area which allows a maximization of the discharge volume. The wall-auxiliary anode which surrounds the discharge region can effectively control the charged particles in the discharge region. The surface discharge DC-PDP cell structure which combines the surface discharge and the wall auxiliary anode has been show the improvements of discharge characteristics due to the strong non-uniform electric field. We investigated and compared the discharge characteristics of the each cell structures. A special emphasis was given to the effect of the wall-auxiliary anode on the discharge characteristics and we have carried out the experiments of measuring the VUV spectra under the various experimental conditions and cell structures. The wall-electrode DC-PDP cell structure and surface discharge DC-PDP cell structure show high luminance, low discharge maintaining voltage, and high discharge efficiency.
3:20 PM		PS+FP-MoA-5 Study of VUV Emission Spectra from AC Plasma Display Panel H.S. Jeong, B.J. Shin, J.H. Seo, C.K. Yoon, K.W. Whang (Seoul National University, Korea) Time-dependent behavior of various plasma variables of an AC-PDP(Plasma Display Panel) cell such as the electron temperature, the densities of electron, ions and excited species, and the surface charge distribution are obtained by solving the time-dependent, 2-dimensional multi-fluid equations for He-Xe mixture. Using the image intensified CCD camera, we measured the time variation of 147nm VUV Xe(³P₁) resonance emission as well as other spectral lines from a specially fabricated AC PDP panel driven at 80kHz and compared with the simulation result. The precise measurement of the temporal behavior of VUV emission spectra will allow to determine a few unknown rate constants in the plasma chemistry model and thus obtained agreement between simulation and experimental results will enable us to use the simulation results for the better understanding of plasma in a plasma display panel and as a tool for the better design of discharge cell and driving scheme.
3:40 PM	Invited	PS+FP-MoA-6 The "Invariant" and "Invariable" Scaling of Planar Magnetron Sputtering from 200 mm Silicon to Meter Square LCTFT Display Applications R.E. Demaray, S. Sawada, D. Meakin, W.J. Yoo (Applied Komatsu Technology, Japan) While semiconductor manufacturing has stalled at the transition from 200 to 300 mm manufacture, the so called thin film transistor, TFT Liquid Crystal industry has vaulted through three or more generations and half a dozen major increases in substrate size in as many years. Today, the so called generation 3.5 equipment takes the industry to the 600 X 720 mm size. Designs are on the drawing boards for the fourth generation which will increase single substrate, isolated process chamber thin film deposition technology to meter square capability. At the same time, the need to achieve semiconductor levels of film quality improvement and yield enhancement have driven the value of scaleable plasma processing designs to a level never imagined by the users of tiny 200 mm silicon substrates. The challenges of "design-once" planar magnetron technology will be discussed with recent results for both the source design rules and the resulting economies of both scale and ownership.
4:20 PM		PS+FP-MoA-8 Advantages of Using A High Density Plasma Source for FPD Plasma Processing. J.P. Holland, A. Demos, N. Tran (Lam Research Corporation) The manufacture processes for flat panel display (FPD) substrates has typically involved either wet chemistry or use of low density, parallel plate plasma sources. Issues with these methods include low processing rates and poor process uniformities. An alternative to the these techinques which have till recently been unavailable commercially is the use of a high density plasma source for plasma processing of the large area panels. High density plasma sources have become common place for wafer-based manufacturing, however, not all of the high density plasma sources proved to be scalable for the large area applications. One exception to this problem of scalability of high density sources is the planar, inductively coupled plasma source. Operation of this source on substrates as large as 600x720 mm have been demonstrated. Issues with processing rates can be overcome when using these high efficiency sources and process uniformities can be much lower than are achieved with either wet chemistry or RIE etching. Results etching of a variety of films which are involved in the plasma processes for both AMLCD and FED applications will be discussed.
4:40 PM		PS+FP-MoA-9 Electron Cyclotron Resonance Plasma Etching of Oxides and SrS and ZnS-based Electroluminescent Materials for Flat Panel Displays J.W. Lee, M.R. Davidson, B. Pathangey, P.H. Holloway, A. Davydov, T.J. Anderson, S.J. Pearton (University of Florida, Gainesville); F. Ren (Bell Laboratories, Lucent Technologies) We investigated different ECR plasma etching chemistries to optimize dry etching processes of SrS and ZnS-based electroluminescent materials for flat panel display devices. The stacked structure consisted of Al₂O₃, AlSnO_X, InSnO_X, SrS, ZnS and TiW layers. The plasma chemistries we investigated included CH₄/H₂/Ar, SF₆/Ar, Cl₂/Ar, BCl₃/Ar and IBr/Ar. We also studied effects of microwave power (or ion flux) in the range of 0-1000 W, rf chuck power (i.e. dc bias or ion energy) from 50-450 W, pressure (1.5-10 mTorr) and plasma composition to the etch rates. Etch rates of each component of the device structures in the high microwave power (> 800 W) ECR etching recipes were about one order of magnitude higher than conventional RIE mode at the same conditions. For examples, SrS could be etched at > 3000 Å/min in ECR SF₆/Ar plasmas which were remarkably higher compared to RIE etching where typical etch rates were < 200 Å/min. Surface stoichiometries and residues for each component of the whole structures were also examined using Auger Electron Spectroscopy, and compared to the control samples. Fluorine and chlorine containing residues were detected after etching of oxide layers, (Al₂O₃, AlSnO_X and InSnO_X), but were less evident on the sulphide-based materials. We also found that chlorine based plasma recipes could cause preferential loss of Ti from TiW layers. Etching of an entire 2.6 micrometer stacked structure could typically be achieved in about 40 mins in non-corrosive CH₄/H₂/Ar ECR plasmas.
5:00 PM		PS+FP-MoA-10 Arc-Suppressed RF Magnetron Sputtering for ITO Film Preparation using Time Modulation Technique K. Ishibashi, K. Watabe, H. Nogami, O. Okada (Anelva Corporation, Japan) Tin-doped indium oxide (ITO) films are extensively used as conductive transparent electrodes in flat panel displays such as liquid crystal display (LCD). In mass production, ITO films are being generally deposited by dc magnetron sputtering owing to its low cost electrical setup and ease of controllability. The recent progress in LCD technology requires ITO films of lower specific resistivity. In comparison with dc magnetron sputtering, ITO films of lower specific resistivity are obtained by rf magnetron sputtering. In rf magnetron sputtering of ITO target, however, an extraordinary arcing phenomenon that an arc-spot moves around along the most eroded track on the target surface often breaks out during the sputtering. This phenomenon makes film preparation unstable, and results in a serious problem in mass production of ITO films. It was found that the outbreak of the arc could be successfully suppressed by means of time modulation technique. Practically, time-modulated rf power was supplied to the target with frequencies in a range of 100-200Hz and duty ratios of 75-90%. Specific resistivity of films deposited on glass substrates at 200°C with an optimum oxygen gas flow rate was 1.4x10^-4Ωcm. This technique provides an effective way to suppress the outbreak of the arc and to prepare ITO films of low specific resistivity.