G Poster

Wednesday, April 12, 2000 5:00 PM in Room Atlas Foyer

GP-1 Characteristics of Metal-Coated Optical Fiber and Its Manufacturing Processes
W-H. Lee, S-M. Lin, T-M. Hu (National Taipei University of Technology, ROC); Y.Z. Zhang (Université Libre de Bruxelles, Belgium)
There are three different metal-coated optical fibers have been successfully produced by the methods of sputtering, electroless and electrical plating. The commercialized plastic-coated optical fiber was firstly stripped in the alcohol and then immersed into the SnCl2 solution for sensitization treatment. Ni or Cu electroless or sputtering coating processes thereafter induces the conductivity of optical fiber. The thickness of metal coating layer, Fe-Ni alloy, Ni, or Cu is increased in the nickel-sulfurmate and copper plating solution. A maximum thickness of 70 mm coating layer is achieved. Detailed plating procedures were presented in this research work. The characteristics of wave propagation phenomena in metal-coated optical fiber were examined. A laser beam with Gaussian profile was injected into the metal-coated optical fiber to investigate the variation of wave profile and intensity versus to the temperature ranging from R.T to 200oC. The weldability of metal-coated optical fibers are also tested by conventional Sn soldering and microwelding. All of the specimens were examined in SEM and EDX.
GP-2 Investigation with Regard to PVD-Arc-Coatings on Polyamid Fabrics
Y. Dietzel, W. Pryzborowski, G. Nocke (University of Applied Sciences Zittau/Görlitz, Germany); F. Hollstein, B. Scholz (TECHNO-COAT Oberflächentechnik GmbH, Germany)
In contrast to conventional metallization procedures for textile fibres and fabrics the PVD technologies allow one to produce a defined structure of thin films on most fabric surfaces. This permits many new applications especially for so-called Technical Textiles. The generation of properties such as supremely anti-static, electrical conductivity, shielding against electromagnetic radiation, protection against heat rays, chemical resistance, bacteria contamination, increased thermal stability and so on are only some examples. In the paper initial results for coatings on divers polyamid fabrics are described. The experimental basis was an industrial PVD-coating device of the HTC 1000/4 ABS@super TM@ ( (HAUZER Inc.) type. Coatings were performed in the arc-deposition mode. The aim of the study was to investigate some relevant correlations between surface structures or functionalities of PVD-coated fabrics, respectively, and main process parameters. Especially tribological and electrical properties were considered. Masked coatings were performed by using the so-called CoatingWatch@super TM@ to reduce the experimental time exposure. Titanium and zirconium targets served as deposition materials. Nitrogen and acetylen were chosen for reactive processing.
GP-3 Application of Plasma Immersion Ion Implantation for Seeding Cu Electroplating on ULSI interconnects
S.Y. Chiu (National Chiao Tung University, Taiwan, ROC); J.H. Lin (National Tsing Hua University, Taiwan, ROC); Y.L. Wang (National Chiao Tung University, Taiwan, ROC); I.C. Tung (National Chiou Tung University, Taiwan, ROC); H.C. Shih (National Tsing Hua University, Taiwan, ROC); M.S. Feng (National Chiao Tung University, Taiwan, R.O.C.)
Copper has been well recognized as an alternative metallization material to replace Al alloys due to its lower resistivity, higher allowed current densities, higher electromigration resistance and increased scalability. In 1997, IBM reported the full copper wiring for 0.25? CMOS devices, which invoked a myriad of research activities in development the Cu metallization technologies for ULSI multilevel interconnections. Currently, the method for copper metallization in ULSI technologies is primarily based on copper electroplating. However, in the electroplating process, one of the essential requirements is to have a continuous Cu seed layer. In this study, a new seeding technology for electroplating process was proposed and shows favorable feasibility on the application for ULSI interconnection. This copper electroplating process is especially attractive, in which two different kinds of conducting seed layers, i.e. Cu and Pd, can be prepared by plasma immersion ion implantation. The metal ions were implated uniformly and continuously into adhesion and braaier metals, i.e. TaN/Ta, and the suitable implantation bias and doses for seeding copper electroplating were determined by RBS and SIMS analyses. The material properties and surface morphology of the electroplated copper films were evaluated by using AFM, SEM, XRD, and peel test. In addition, gap filling ability in Damascence Cu electroplating, especially in high-aspect-ratio cavities, would also be discussed.
GP-4 On the Mechanism of Self-deceleration of the Fine Oxide Film Growth
D.G. Moukhambetov, O.V. Chalay (Karaganda Metallurgical Institute, Kazakhstan)
The object of this work was to investigate kinetics of the two phase oxide film growth in going from the range of process control by transfer of Me@super 2+@ ions by means of electric field in the oxide to the range of diffusion control. It is attained that film thickness h - time oxidation ( relationship in the range of diffusion control is logarithmic function, whereas Kabrera and Mott's theory gives square law of the film growth. In our work analytical treatment of obtained data was made on the basis of this theory, but we suppose that self-deceleration of the film growth is caused not by attenuation of the electric intensity in the film because of increase of h but by shielding influence of the space charge of diffusing ions and electrons in that oxide film. With that aim in view the Debye shielding distance for plasma substance state in the oxide film was taken into consideration. Estimating calculations of this law parameters quantitatively corresponding with the literature data were made.
GP-5 Improved Etching Characteristics of Silicone-Oxide by the Enhanced-ICP
B-H. O, S-G. Park, J.-K. Jeong, S-H. Rha (Inha University, South Korea)
We have proposed and developed a novel plasma process technique, named 'Enhanced-ICP', which uses periodic on/off control of weak axial magnetic field to provide better uniformity and higher etch rate. The E-ICP process, so far, is considered as a damage-free technique with much improved characteristics. It has already showed better spatial uniformity than 1% and much improved etch rate within a diameter of 10 cm for a photo-resist etch process. As it is necessary to develop this technique for other processes also and the etch of SiO@sub 2@ is important for most of recent semiconductor fabrication, the E-ICP is tested with the CF@sub 4@ gas plasma. The adoption of E-ICP process for SiO@sub 2@ etch with CF@sub 4@ gas also provides better etch profile and etch rate than a normal ICP process at some other specific on/off frequency of weak axial magnetic field than that of oxygen gas. Although this specific frequency characteristics of each gas plasma has been being studied, it is not understood so clearly yet. The SEM picture reveals that the vertical etch rate increases about 1.3 times larger than that of a normal ICP, while side etch rate does not change noticeably, to provide more vertical slope profile than normal. Furthermore, the comparison of etched bottom profiles shows that the E-ICP process achieves no distortion of etched bottom profile, while a normal ICP gives trench-type distortion for a pattern located at the outer position of a sample holder.
GP-6 Characterization of Off-Plane Double Bend Filtered Cathodic Vacuum Arc system
B.K. Tay, S.P. Lau, S. Shi, G.F. You (Nanyang Technological University, Singapore)
Abstract An improved Filtered Cathodic Vacuum Arc (FCVA) system consisting of an Off-Plane Double Bend (OPDB) magnetic filter has been developed recently. Rather than the 90-degree single bend system, the OPDB has the relatively better ion transmitting efficiency, separates more macroparticles from cathodic arc plasma by the way based on the indirect trajectories between cathode and substrate. To describe the plasma motion in the torodal solenoid of the OPDB, we use a simulation way based on a modified drift approximation model. Upon knowing the initial plasma density and energy, the trajectory and exact position of an ion along the duct torus can be calculated by the model. From simulation, we can obtain the ion number in the torus as a function of ion density and current. The effect of different system parameters such as the magnetic field and duct bias voltage was investigated. It shows that increasing the filtering magnetic field will result in higher ion flux density and transportation efficiency. There is also an optimum duct bias to obtain the highest ion density. The higher arc current will provide the higher ion density. The ion energy, plasma potential and saturation current were measured by Farady cup, Langmuir and current probe, our simulation works were found to be in good agreement with the experiment. Keywords: filtered cathodic vacuum arc; off-plane double bend; plasma motion
GP-7 Investigation of Microparticles Emission from Plasma of Gas Discharge with Hollow Cathode
A.S. Zolkin, V.V. Prihodko, A.A. Maksyashin (Novosibirsk State University, Russia)
The plasma of gas discharge with hollow cathode is considered as a reactor in which microparticles are synthesized. Clusters and microparticles of chemical compounds can be formed during atomization of the cathode material and collisions between plasma components when the formation of the new phase occurs mainly on ions. The emission of Cu, Mo, Ta, and Ni microparticles from the plasma of hollow cathode (30 mm in diameter, 120 mm long) with discharge in argon (P = 0.05 Torr) is studied in the present work using the molecular beam technique. Plasma flew into the chamber with reduced pressure through a 3 mm hole in the front part of hollow cathode and interacted with the surface of silicon single crystal at a distance of 2 - 30 mm from the nozzle hole of the cathode. Films and particles on silicon surface were studied with the help of scanning (SEM) combined with X-ray microanalyzer. The back-scattering electrons (BSEM) technique was used as an additional tool. Of special interest are the new data on the emission of copper microparticles with the mean size of 50 micrometer (in liquid state). The flow of copper particles from the plasma is about 2*10@super 13@ atoms per second. We measured the ion current (0.1 - 10 µmA) at the total discharge current (10 - 60 mA) in the hollow cathode. The results obtained in the present work can be of interest for researchers in the field of plasma chemistry, gas discharge physics, as well as for those studying cluster formation in plasma and the synthesis of thin films.
GP-8 Time-resolved Langmuir-Probe Measurements in Pulsed DC Sputtering Magnetron Plasma
H. Bäcker, J.W. Bradley (UMIST, United Kingdom); P.J. Kelley, R.D. Arnell (University of Salford, United Kingdom)
The use of pulsed DC magnetron plasma sources is now of great interest for the production of technologically relevant thin films and coatings. This technique is particularly important in the deposition of oxides and nitrides in reactive sputtering processes. However, to date there has been little published work in the area of the diagnosis and modelling of the time dependent plasma parameters in these discharges. We shall present preliminary time resolved Langmuir-Probe measurements of the plasma density, electron temperature, plasma and floating potentials and electron energy distribution function at different positions in the plasma and for a range of pulsing frequencies (5 to 350 kHz). Through these results, we shall relate the time dependent plasma parameters to the applied voltage and current waveforms and then to the structure and properties of the deposited coatings.
GP-9 The Study of Glow Discharge at Atmospheric Pressure by Capillary Electrode
Y.H. Lee, Y.J. Sung, G.Y. Yeom (Sungkyunkwan University, Korea)
In industrial plasma processes, vacuum systems have been generally used for thin film deposition, dry etching, and surface treatments. To remove costly vacuum systems and to apply to various other situations, low temperature plasmas generated at atmospheric pressure such as dielectric barrier discharges, atmospheric microwave discharges, etc. are actively studied in these days. In this study, an atmospheric pressure low temperature plasma generated by capillary electrodes was investigated for the application of semiconductor wafer cleaning processes. The characteristics of the plasmas were studied as a function of capillary aspect ratios, various gas mixtures, and electrode distance. The atmospheric pressure discharge was created in a Pyrex glass chamber containing parallel plate electrodes. The powered electrode and the ground electrode were both 12cm in diameter and were made of stainless steel. The bottom of the powered electrode was covered by Teflon or glass with various capillary holes to prevent the transition of the discharge from glow discharge to an arc by limiting the current. The distance between two electrodes could be removed from a few millimeters to a few centimeters. Various gases such as He, O@sub 2@, Ar, and N@sub 2@ have been used, but the most uniform and stable discharge were obtained when He was the main component of the gas mixture. Using the optical emission spectroscopy (OES), a large amount of radicals and ions existed in the atmospheric pressure plasma could be detected in our experimental conditions. Also, using He/O@sub 2@ gas mixtures, organic materials such as photoresist could be removed. In this presentation, the stabilit! ! y of the capillary plasmas depending on various capillary shapes and process parameters will be emphasized.
GP-10 Innovative Concepts in Cleaning Technology for Improved Coating Quality
T. Eckardt, H.B. Gröninger, U. Schaal (Fraunhofer Institute for Surface Engineering and Thin Films, Germany)
Surface pre-treatment and removal of contamination are important factors in the whole manufacturing process preceding the deposition of a coating. The status of the surface effects film growth and adhesion on the substrate which have to become optimum for any functional coating. There are not only different requirements for cleanliness but also various technologies and methods proposed. In this presentation water-based cleaning agents and hydrocarbon-based solvents are compared, clearly demonstrating advantages for the aqueous system. This is especially true for those coating systems where an effective plasma etching prior to deposition is missing. As a conclusion from these results an overall concept for a new demonstration plant has been developed and realised. It is now possible to prepare any kind of material (steel, aluminium, copper, glass, ceramic etc.) contaminated with organic and/or inorganic compounds due to the combination of single cleaning steps. Thereby the cleaning procedure must be adapted to material, contamination and consecutive manufacturing. Available sections include degreasing, activation, passivation (to prevent corrosion), multistage rinsing and finally drying by an innovative system combining hot-air and vacuum. Examples will demonstrate the effectiveness of this concept which is highly reduced in the use of cleaning agents and water resulting from intelligent process cycles and other means assisting the cleaning process. Furthermore an extended lifetime and high quality of functional cleaning bathes can only be assured by quality control measuring specific properties like conductivity or surface tension.
GP-11 Large Area High Density Plasma Source by Helical Resonator Arrays
S.-G. Park, B-H. O, S.H. Lee (Inha University, South Korea)
An array of smaller unit plasma sources have been be used for generating larger area plasma to process large substrates such as flat panel display (FPD). In this work, four helical resonators are distributed in a 2x2 array by modifying upper part of the conventional reactive ion etching (RIE) type LCD etcher. Since the resonance condition of the individual unit can be easily found by adjusting the tapping position of RF signal to the helical antenna, one RF power supply is used for delivering the power efficiently to all four helical resonators without an impedance matching network. Previous work of 2x2 array inductively coupled plasma (ICP) requires one matching circuit to each ICP antenna for more efficient power delivery. @footnote 1@ Distributions of ion density and electron temperature are measured in terms of chamber pressure, gas flow rate and RF power. By adjusting the power distribution among the four helical resonator units, argon plasma density of higher than 10@sup 16@/m@sup 3@ with the uniformity of better than 7% can be obtained in the 620x620mm@sup 2@ chamber. @FootnoteText@ @footnote 1@ C. Chan, U.S. Patent No. 5,653,811 (1997).
GP-12 The Use of Magnetron Arrays for the Deposition of Large-area Oxide Coatings
A.F. Jankowski, M.A. McKernan (Lawrence Livermore National Laboratory)
The sputter deposition of coatings over large areas is often approached through the use of large, rectangular planar magnetrons. A wide range of applications for large area coatings includes the deposition of dielectric layers on silicon, anti-reflective coatings on glass, corrosion resistant coatings on metals, and more recently, multilayers for x-ray optics. An alternative to the rectangular magnetron can be beneficial to minimize the expense of target materials and the cost of large deposition source(s). One feasible approach is to use an array of circular planar magnetrons. In a prior demonstration, the use of two linear arrays of three, one-inch diameter magnetron sources as operated in the dc mode provided an effective means to deposit uniformly spaced multilayers across a 15 cm wide path. A greater number of synchronously operated, larger diameter sources is required for wider coating paths. Presently, we investigate the use of a linear array of three-inch diameter magnetron sources operated in the rf mode to deposit an oxide target material across a path in excess of 70 cm. Results are given for the performance of the planar magnetrons in depositing a 1 µm thick alumina coating. This work was performed under the auspices of the US Department of Energy by Lawrence Livermore National Laboratory under Contract No. W-7405-ENG-48.
GP-13 Dry Etch Characteristics of Al-Nd Films for Thin-film-transistor Liquid Crystal Displays
H.R. Han, Y.J. Lee (Sungkyunkwan University, Korea); K.H. Oho (National Institute of Technology and Quality, Korea); M.P. Hong (Samsung Semiconductor, Korea); G.Y. Yeom (Sungkyunkwan University, Korea)
Al-Nd films are generally used for TFT-LCD gate electrode application due to the high heat tolerance on hillock formation during the post-annealing processes. Currently, the patterning of Al-Nd films is done by wet etching and, due to the material and chemical selectivity of the wet etching, problems such as Nd residues and irregular electrode line shapes are remained. Therefore, dry etching techniques are actively investigated to replace for gate electrode etching of the next generation TFT-LCD. In this study, Al-Nd thin films deposited on glass were etched using magnetized inductively couped plasmas(MICP) and the etch characteristics were investigated as a function of gas conbination, pressure, dc self-bias voltage, and inductive power. Gas combination of Cl@sub 2@, BCl@sub 3@, and HBr were used with pressures in the range of 5mTorr to 30mTorr, dc self-bias voltages from -50V to -200V, and inductive powers from 400W to 800W. Using Cl@sub 2@/BCl@sub 3@ gas mixtures, the etch rates of Al-Nd films less than 1000Å/min and etch selectivities over photoresist less than 0.5 were obtained due to the non-volatile Nd in the Al-Nd thin films. Also, some defects were observed on the surface of glass after the etching of Al-Nd originated from the remaining Nd. On the other hand, the use of BCl@sub 3@/HBr chemistry increased Al-Nd etch rate close to 1500Å/min and etch selectivity close to 1. In addition, barely no surface defects could be found with this chemistry. Using the plasma diagnostic tools such as optical emission spectrscopy(OES) and quadruple mass spectroscopy(QMS), the etching mechanisms with these chemistries were investigated. Variations of surface composition of the Al-Nd samples during the etching and after the etching for various gas mixtures were also investigated using X-ray photoelectron spectroscopy(XPS). The etch profiles and surface defects were observed with a scanning electron microscope(SEM). @FootnoteText@ Enter each footnote and reference separated by a blank line.
GP-14 Characteristics of Magnetized Inductively Coupled Plasma Source for Large Area Flat Panel Display Applications
Y.J. Lee, H.R. Han, G.Y. Yeom (Sungkyunkwan University, Korea)
In order to achieve the performance required for higher resolution flat panel display(FPD) devices of next generation, improved dry etch processes currently indispensable technology for semiconductor industry are required for volume manufacturing and superior critical dimension control. Most of the dry etching equipments currently available for FPD devices are based on the capacitive plasma excitation. These types of etch equipments, however, are suffered from relatively low plasma densities, therefore low etch rates. To increase the etch rates, one of the high density plasma sources, inductively coupled plasmas (ICP) source is generally studied for the application, but plasma nonuniformity which is key technical requirement for FPD process is still remained as a problem. In this study, to improve both the plasma density and the uniformity of ICP source, permanent magnets and Helmholtz type axial electromagnets were used to the conventional ICP source and the effects of various magnet combinations and process conditions on the polysilicon etch rates and etch uniformities were studied. The permanent magnets having 3000G on the magnet surface were arranged along the chamber wall by varying center-to-center distance of the magnets, and also 20Gauss of the Helmholtz type axial electromagnet was added to the permanent magnet to improve plasma density. There was a strong relationship between the combination of the magnets and plasma characteristics such as density and uniformity. Under optimized combinations of both the permanent magnets and the axial electromagnets around the chamber wall, the plasma uniformity better than 4% could be obtained while maintaining high plasma ion densities higher than 3@¡¿@10@super 11@cm@super 3@. In the application to poly-silicon etching processes, poly-silicon etch rates about three times higher than those etched using the conventional (non-magnetized) ICP plasmas could be obtained in our experimental conditions. To understand the effects of various magnets and process conditions on the plasma characteristics, a quadrupole masss spectrometer (QMS: Hidern Analytical Inc., PSM 500) and a Langmuir probe (Hiden Analytical Inc., ESP) located on the sidewall chamber were used. @FootnoteText@ Enter each footnote and reference separated by a blank line.
GP-15 Direct Temperature Monitoring for Plasma Implantation of Semiconductors
X.B. Tian, B.Y. Tang, Z.M. Zeng, X.C. Zeng, P.K. Chu (City University of Hong Kong)
Accurate and reliable in-situ temperature monitoring in SPIMOX (Separation by Plasma Implantation of Oxygen) and hydrogen PIII (Plasma Immersion Ion Implantation) - ion-cut is crucial to the success and yield of the two SOI (silicon-on-insulator) fabrication processes. In the former process, the silicon wafer temperature must be kept at above 600@super o@C and in the PIII - ion-cut process, the wafer temperature must be kept below 300@super o@C throughout the experiment. Remote temperature sensing techniques using pyrometers have several drawbacks even though pyrometers are safer to use as they are usually positioned outside of the vacuum chamber. In this paper, we present our direct temperature measurement approach using a thermocouple directly connected to the sample stage. Our special design eliminates many arcing-related problems and enables the device to function properly at implantation voltages over 50 kV. We will present our measurement system and experimental data.