Riccardo d'Agostino, Univ di Bari
Wei Lee, Science-Based Park
Buddy Ratner, Univ of Washington
Michael R. Wertheimer, Ecole Polytechnique de Montreal
Proceedings published as Volume 544
of the Materials Research Society
Symposium Proceedings Series.
* Invited paper
FTY: NEW TRENDS IN APPLICATIONS OF PLASMA PROCESSING OF POLYMERS
Sunday, November 29, 1:00-5:30 p.m.
Salons J/K (Marriott)
This tutorial will highlight the most relevant developments in four topics which can be considered the motor powering applications of plasma processing of polymers: activation for improving adhesion of metals and dielectrics; transparent barrier coatings for food and pharmaceutical packaging; immobilization of biomolecules for blood contacting biomedical devices and sensors; and low-k dielectric films for microelectronics.
Farzaneh Arefi-Khonsari, Laboratoire de Genie des Procedes Plasma, ENSCP
Ritalba Lamendola, University of Bari
Hans J. Griesser, CSIRO Molecular Science
Richard Timmons, University of Texas at Arlington
SESSION Y1: PLASMA TREATMENTS FOR BIOMATERIALS
Chairs: Pietro Favia and Hans J. Griesser
Monday Morning, November 30, 1998
Essex Center (W)
8:30 AM Y1.1
APPLICATIONS OF PLASMA POLYMER FILMS AS NON-FOULING AND THERMALLY RESPONSIVE COATINGS IN BIOMATERIALS AND MEMS. Y. Vickie Pan , Mimi Mar, Marc M. Takeno, Buddy D. Ratner, University of Washington, Engineered Biomaterials (UWEB), Seattle, WA; Denice D. Denton, University of Washington, College of Engineering, Seattle, WA.
This abstract summarizes part of the continued effort in our group to investigate the applications of plasma polymerized coatings in biomaterials and, more recently, in MEMS (MicroElectroMechanical Systems). Some of the plasma polymers studied include: plasma polymerized triglyme (pp3G) and tetraglyme (pp4G) as non-fouling coatings, and plasma polymerized n-isopropylacrylamide (ppNIPAM) as thermally responsive coatings. In addition to the chemical characterization of the coatings, their performances as non-fouling and thermally responsive coatings on various substrates and MEMS devices are also studied.
The coatings were analyzed by ESCA and FTIR, and the results suggest that retention of much of the monomer structure has been achieved. For example, the elemental composition of pp4G as measured by ESCA showed an atomic composition of 70.1% C and 29.9% O similar to the theoretical composition for a PEG-like surface of 66.7% C and 33.3% O.
The non-fouling properties of the pp3G and pp4G films were verified real time by surface plasmon resonance (SPR) measurements. Cold protein adsorption experiments on pp3G, pp4G and a number of other common MEMS materials also demonstrated the non-fouling properties of the plasma polymerized glyme coatings. The applications of patterned and non-patterned pp4G coatings in MEMS and microfluidic devices are currently being investigated.
The elemental composition of ppNIPAM revealed an atomic composition of 76.8% C, 12.8% N and 10.4% O compared to the theoretical composition of 75.0% C, 12.5% N and 12.5% O for poly NIPAM. The high resolution ESCA carbon 1s scans and FTIR measurements are also supportive of the high monomer retention rate in the plasma polymer coatings. Preliminary testing of the thermal responses of ppNIPAM coatings indicated a phase transition at a temperature slightly above room temperature. Additional tests are underway to further investigate the ppNIPAM film phase transition behavior and its applications in biotechnology.
8:45 AM Y1.2
157 NM VUV PATTERNING OF POLYMER SURFACES FOR THE FABRICATION OF OPTICALLY TRANSPARENT BIOCHIPS FOR APPLICATIONS IN GENOME ANALYSIS. Markus Lapczyna, Max-Planck-Institut f. biophys. Chemie, Goettingen, GERMANY, Giuseppina Padeletti , ICMAT-CNR Monterotondo, ITALY, Michael Stuke, Max-Planck-Institut f. biophys. Chemie, Goettingen, GERMANY.
Ultraprecise patterning of polymer surfaces can be achieved using VUV laser ablation in the vacuum-ultraviolet at 157 nm through laser direct-written silicon membrane (12 µm) contact masks. Ablation rates of typically about 100 nm per laser shot are used. Sub-micrometer channel widths and ultrasmooth surfaces with a surface smoothness in the range of 1 nm can be generated using a rapid prototype technique. This talk will focus on the results obtained for PMMA. The surfaces are carefully characterized by AFM, both inside and outside of the laser ablated area. Evidence for a thin liquid layer formed during the VUV ablation process is seen. Sensors for applications as transparent biochip for genome analysis can be generated.
9:00 AM *Y1.3
RF GLOW DISCHARGE DEPOSITED FLUOROCARBON SURFACES FOR ENHANCED ENDOTHELIAL CELL GROWTH. David G. Castner , Caren D. Tidwell, and Buddy D. Ratner, University of Washington, Departments of Bioengineering and Chemical Engineering, Seattle, WA.
In vascular surgery, the success of synthetic small-diameter grafts (<5 mm) has been limited. Expanded polytetrafluoroethylene (ePTFE), a common material used to fabricate these grafts, does not promote endothelial cell growth. Thus, surface modification strategies that promote the growth of endothelial cells on ePTFE grafts should improve their patency. The aim of our surface modification strategy is to use RF glow discharge (RFGD) deposition to produce multifunctional fluorinated surfaces with optimal protein binding and cell growth properties. RFGD with hexafluoroethane (HFE), hexafluoropropylene (HFP), and perfluoropropane (PFP) monomers was used to deposit films onto tissue culture polystyrene (TCPS) plates containing different mixtures of fluorocarbon species. The surface structure and composition of each material was characterized using X-ray photoelectron spectroscopy (XPS) and static time-of-flight secondary ion mass spectrometry (ToF-SIMS). The in vitro growth of bovine aortic endothelial cells (BAECs) in 10 bovine serum medium seeded at 50,000 and 100,000 cells/well was evaluated after 1 to 3 days in culture using a MTT (tetrazolium salt) assay. After three days of culture the number of cells present on each surface decreased in the order: TCPS > HFP PFP HFE. Thus, variability in fluorocarbon surface chemistry resulted in significant differences in cell growth. In particular, the ratio of CF3/CF2 species in the XPS C1s spectra increased from 0.72 to 0.90 to 1.25 with increasing growth rate, indicating the importance of CF3groups in BAEC growth. Cell distribution and morphology differed significantly on the fluorocarbon surfaces compared with the TCPS surface. Cells on TCPS exhibited uniform spreading and were uniformly distributed over the surface. Cells on the fluorocarbon plasma films were typically smaller in size and tended to be clustered into colonies with more sparsely populated regions observed between colonies.
10:00 AM *Y1.4
SURFACE IMMOBILIZATION OF SYNTHETIC PROTEINS VIA PLASMA POLYMER INTERLAYERS. Hans J. Griesser , Keith M. McLean, Gerrit J. Beumer, Xiaoyi Gong, Peter Kingshott and Helmut Thissen, CSIRO Molecular Science, Clayton, AUSTRALIA.
Plasma surface treatments and plasma polymerized coatings have enabled fabrication of well-performing surfaces for a number of biomaterials applications, particularly tissue culture ware and contact lenses. For other intended applications, however, such as longer-term implantable biomedical devices, improvements are necessary to overcome effects such as excessive and unspecific protein deposition, complement activation, and fibrous tissue formation. Emphasis has increasingly shifted towards the development of coatings that comprise a layer of biological molecules on synthetic materials; the biological molecules thus dictate the interfacial responsese. A thin layer of surface-attached proteins is, however, subject to adverse effects on storage and to enzymatic attack on contact with the biological environment. Synthetic biopolymers (ëpeptoidsí) consisting of N-substituted amino acids promise to achieve better storage stability as well as resistance to proteolytic attack. We have used various plasma polymer interfacial layers to develop broadly applicable strategies for covalently attaching peptoids onto synthetic bulk materials. Of particular interest are peptoids with Gly-Nleu-Pro and Gly-Pro-Nleu repeat structures, since they can form triple helices that mimic those of collagens. The peptoids are coupled via their N-termini or their C-termini, either directly onto plasma-generated amine, aldehyde, or carboxylic acid groups, or via a further, highly hydrated ëspacerí layer. Plasma conditions were optimized, the functionalised surfaces characterized, and factors influencing the subsequent interfacial coupling reactions investigated. When observing biomolecules spectroscopically on surfaces, it is perilous to conclude that covalent immobilization has indeed taken place, since they also physisorb readily to many surfaces. To obtain direct evidence that an intended protein immobilization strategy has occurred, we used small molecules to study immobilization reactions, and the novel method of Surface-MALDI spectroscopy to probe for adsorbed peptoids. Peptoid coatings have given promising results for use with silicone-based contact lenses and in attachment and proliferation asays with anchorage-dependent cell lines.
10:30 AM Y1.5
RFGD PLASMA TREATMENT FOR TUBULAR ePTFE VASCULAR PROSTHESES. Diego Mantovani , Martin Castonguay, Michel Fiset, Gaetan Laroche, Quebec Biomaterials Institute and Department of Metallurgy, Laval University, Quebec City, CANADA.
Low pressure plasma surface treatments may offer a valid alternative for the improvement of the vascular prosthesis challenging hemocompatibility. An experimentally simple and low-cost plasma reactor was designed, developed and characterized in order to successfully treat the inside of 10 mm i.d. arterial prostheses, 20-150 mm long. Moreover, the evolution of the surface composition as a function of storage time was also investigated. The plasma reactor consists of a cylindrical Pyrex glass tube, with an inlet for gas injection 5 cm below its upper end, vertically placed under a glass bell jar. Three capacitively coupled copper electrodes are attached at the middle of the tube. Gas pressure in the chamber is kept constant by using a pressure controller. The plasma can be operated in a RF power range from 10 to 100W at 13.56 MHz frequency using a RF power generator and an automatic matching network. Microporous 10 mm i.d. ePTFE vascular prostheses were kindly supplied by Baxter, CA. High purity ammonia gas was used for all plasma treatments in order to bind amine-groups on the prostheses surface. All plasma treatments were accomplished at 20 W (13.56 MHz), during 250 sec and with a NH3 pressure of 300 mTorr into the bell jar. After treatments, a certain number of treated prostheses were stored into a laminar flow hood for further studies. X-ray photoelectron spectroscopy (XPS) has been used to characterize the modified surfaces. For all untreated and NH3 plasma-modified vascular prostheses results show that a substantial amount of nitrogen and oxygen is incorporated into the surface of the treated prostheses and that fluorine peak is considerably reduced. Right after the treatment, XPS revealed a nitrogen concentration up to 19,8%, and a N/C ratio up to 0.45. The presence of oxygen, between 1,6% and 4,8%, is probably due to the reaction occuring with atmospheric O2 or water vapor during the sample transfer from the plasma chamber to the spectrometer. The evolution of the N/C, O/C and F/C ratios was also investigated. Results show that the N/C ratio remains almost constant as a function of time, while the F/C ratio decreases with time on the ePTFE surface at the benefit of O2 concentration that reaches 14,5% after 80 days.
10:45 AM Y1.6
IMMOBILIZATION OF -CHYMOTRYPSIN ON O2-RF-PLASMA FUNCTIONALIZED POLYETHYLENETEREPHTALATE (PET), POLYPROPYLENE (PP) AND POLYSTYRENE (PS). R. Ganapathy , S. Manolache, University of Wisconsin-Madison, Engineering Research Center for Plasma-Aided Manufacturing, Madison, WI; M. Sarmadi, University of Wisconsin-Madison, School of Human Ecology, Madison, WI; and F. Denes, University of Wisconsin-Madison, Engineering Research Center for Plasma-Aided Manufacturing, Madison, WI.
Two main reasons that both scientists and technologist are attracted to this subject are: firstly the results of these investigations could lead to the use of immobilized enzymes and oligonucleotides as stable and renewable industrial catalysts, and secondly this research might help to understand the influence of heterogeneous environments (most of the intracellular biomolecules work under such conditions) on the biomolecules-driven reactions. RF-plasma-mediated implantation of -C=O functionalities onto PET, PP and PS substrate surfaces was efficiently performed under oxygen and argon discharge conditions, and the immobilization of -chymotrypsin has been successfully accomplished. It has been shown that treatment times as short as 0.5-2 minutes and RF powers as low as 100 W (in a pressure range of 100-300 mTorr) are sufficient to induce the desired surface chemistry using a parallel plate 40 kHz, capacitively coupled (diameter of disk-shaped electrodes: 20 cm; gap: 2.5 cm) reactor. The enzyme was covalently bound to the substrate under post plasma, , conditions by reacting the primary amine groups of the enzyme molecules and the plasma-created carbonyl functionalities of the polymeric substrates. The increased surface roughness of plasma modified morphologies and the similar topographies of enzyme-coated substrates are indicative of the presence of competitive functionalization/ablation reactions and the successful immobilization of the biomolecules. The presence of specific NH stretching and amide II deformation absorptions (1480-1580 and 1580-1700 cm-1) in the ATR-FTIR spectra, and the consistent surface atomic composition of the substrates with the immobilized enzyme layer, after repeated washing, swelling (DMSO)/washing and drying cycles, clearly indicate that the chymotrypsin was covalently attached to the substrate. It has also been shown that the immobilized enzyme is stable and that it can be successfully used in many cycles.
11:00 AM Y1.7
THE EFFECT OF LINEAR AND CYCLIC PRECURSORS ON THE MOLECULAR STRUCTURE OF ETHER-RICH PLASMA-DEPOSITED FILMS. Erika E. Johnston and Buddy D. Ratner, University of Washington, Engineered Biomaterials, Seattle, WA.
Ether-rich, plasma-deposited films are of interest as biomaterials because of their ability to lessen protein adsorption and cell adhesion. To determine whether the molecular structure of the film influences biofouling resistance, films were deposited from linear and cyclic plasma precursors. Here we report the results of a detailed analysis of the chemistry, structure and wettability of these films. Plasma precursors consisted of a series of four linear oligo ethylene glycol dimethyl ethers (oligoglymes) (CH3-O-(CH2CH2O)n-CH3, n = 1-4) and a corresponding series of cyclic oligomers -(CH2CH2Om-: dioxane, (m=2); 12-crown-4 ether, (m=4); and 15-crown-5 ether (m=5). The surface analysis is based upon a combination of x-ray photoelectron spectroscopy (XPS), time-of-flight SIMS (TOF-SIMS), and dynamic contact angle measurements. From the analysis, oligoglyme plasma-deposited films appear to consist of a carpet of randomly branched, methyl-terminated chains of -(CH2CH2O)- repeat units and are generally free of hydroxyl groups and hydrocarbonaceous domains. TOF-SIMS spectra suggest that films deposited from larger molecular weight precursors are more loosely crosslinked. This conclusion is supported by dynamic contact angle analysis performed at high and low travel speeds. Surface structural models will be proposed that can account for many aspects of the oligoglyme PDF high mass TOF-SIMS spectra. Based on adventitious binding of sodium and potassium cations, and on the PEO backbone-like aspects of the TOF-SIMS spectra, it is concluded that the outermost surface of crown ether films consist predominantly of intact ring structures. TOF-SIMS analysis of dioxane films suggests the presence of hydroxyl groups pendant to an unsaturated hydrocarbonaceous matrix and the presence of ether-carbon bearing precursor moieties.
11:15 AM Y1.8
PLASMA STERILIZATION: SPORE DESTRUCTION BY MICROWAVE PLASMAS. Sophie Lerouge , L'Hocine Yahia, Maryam Tabrizian, Ecole Polytechnique, Research Group on Biomechanics and Biomaterials, Montreal, CANADA; Michael R. Wertheimer, Alexandru C. Fozza, Ecole Polytechnique, Dept of Engineering Physics, Montreal, CANADA; Richard Marchand, Montreal Heart Institute, Montreal, CANADA.
Gas plasma sterilization is an alternative to ethylene oxide for clinical reprocessing of polymeric medical devices. Presently, two commercial sterilizers, namely Sterrad and Plazlyte, use plasma technology in combination with chemical agents. However, little is known about plasma effects on microorganisms. The aim of this study is to better understand the mechanisms of spore destruction, and the role of various plasma species in laboratory and commercial sterilizers. Bacillus subtilis spores (about 107 per batch) were deposited on the flat bottom of special glass vials, in the form of a monolayer, following which they were subjected to a cold microwave plasma. Spore mortality was calculated based on the number of colonies regenerated on agar gels after 24 hours. We have studied the effect of plasma gas composition on the mortality of spores, and also the efficacy of vacuum ultraviolet radiation (VUV), by subjecting spores to VUV radiation and or atomic oxygen (1). Finally, treated and untreated spores were observed by scanning electron microscopy (SEM). Plasmas demonstrated varying degrees of spore destruction, the number of surviving spores decreasing with increasing exposure time. The mortality rate of spores was found to vary with gas composition between less than a 2 log decrease up to a 6 log decrease within 8 minutes. The efficacy of VUV light was found to be lower than all direct plasmas, and this was also true when samples were placed in a low pressure oxygen atmosphere containing reactive species created by VUV radiation. SEM examination showed that even after 15 minutes of direct plasma exposure, spores were only partially etched, leaving smaller structures and microscopic residues. In conclusion, plasma can be highly efficient in the destruction of spores. However, the fact that it is also known to rapidly etch synthetic polymers may limit its application in sterilization, and it must be studied further.
11:30 AM Y1.9
COMPARISON OF PROLIFERATION AND GROWTH OF HUMAN KERATINOCYTES ON PLASMA CO-POLYMERS OF ACRYLIC ACID/1,7-OCTADIENE AND SELF ASSEMBLED MONOLAYERS. David B. Haddow , Richard M. France, Robert D. Short, Laboratory of Surface and Interface Analysis, Dept of Engineering Materials, University of Sheffield, Sheffield, UK; Sheila MacNeil, Rebecca A. Dawson, Dept of Medicine, Clinical Sciences Centre, University of Sheffield, Northern General Hospital, Sheffield, UK.
Plasma co-polymers (PCPs) of acrylic acid/1,7-octadiene have been characterised using X-ray photoelectron spectroscopy (XPS). The use of a hydrocarbon diluent in the monomer feed allowed the deposition of films with controlled concentrations of carboxylic acid functional groups. Human keratinocytes were cultured onto these PCP surfaces, tissue culture polystyrene (TCPS) and collagen I. The degree of keratinocyte attachment was measured over 24 hours and cell proliferation and growth monitored over 1, 3 and 7 days using optical microscopy. Mitochondrial activity (MTT) and DNA concentrations were also measured at these time points. Cell attachment and DNA assays on the PCP surfaces were compared with 3 self assembled monolayer systems comprising (a) pure gold, (b) pure acid, and (c) pure hydrocarbon functionalities. Carboxylic acid functionalities on the PCP surfaces promoted keratinocyte attachment compared with pure hydrocarbon surfaces, with the optimum level of attachment seen with surfaces containing less than 5 acid groups. The level of attachment on these surfaces was comparable to that seen on collagen I, a preferred substrate for the culturing of keratinocytes. After several days in culture the cells on the acid surfaces were well attached and proliferative, forming confluent sheets of keratinocyte colonies. The levels of attachment and proliferation were confirmed by MTT and DNA assays which suggested that low acid concentration (<5) surfaces were performing as well as collagen I. Keratinocytes attached well to gold and acid self assembled monolayers but showed no reaction to hydrocarbon systems. The acid functionality also promoted proliferation and growth of keratinocytes after several days in culture.
Tailored PCP surfaces are shown to be ideal substrates for attachment and proliferation of human keratinocytes, with potential benefits in wound healing.
SESSION Y2: PLASMA TREATMENTS FOR BIOMATERIALS (continued)
Chair: David G. Castner
Monday Afternoon, November 30, 1998
Essex Center (W)
2:00 PM Y2.1
DEVELOPMENT OF PLASMA FUNCTIONALIZED SUPPORTS USED FOR AFFINITY CHROMATOGRAPHY DEVICES. Samy B. Rejeb, Samy B. Rejeb , James F. Lawrence, Food Research Division, Food Directorate, Bureau of Chemical Safety, Health Protection Branch, Health Canada, Ottawa, Ontario, CANADA; Nadine Fischer-Durand, Annie Martel, François Le Goffic, Laboratoire de Biotechnologies de l’Environnement, Ecole Nationale Supérieure de Chimie de Paris, Paris, FRANCE; Michaèl Tatoulian, Farzaneh Arefi-Khonsari, J. Amouroux; Laboratoire de Génie des Procédés Plasma, Ecole Nationale Supérieure de Chimie de Paris, Paris, FRANCE.
In the current investigation of new techniques to functionalize supports useful for the covalent immobilization of biomolecules, we have developed a controlled plasma process allowing the introduction of the appropriate chemical groups on the surface of commonly used materials. Cellulose beads and PVDF membranes were functionalized using non-equilibrium, low pressure plasma of either NH3/H2 mixtures or O2. The ammonia plasma resulted in the introduction of amine functions whereas the oxygen yielded in the introduction of carbonyl and carboxylic groups. These functionalized supports were used to immobilize antibodies in order to obtain immunoaffinity chromatography devices that can be used in sample preparation techniques before analysis. The immobilized antibodies were shown to be covalently retained and active, as they resisted organic solvent medias usually applied to regenerate the supports before a second run. The eluted antigen (a commonly used environmental contaminant) was measured using High Performance Liquid Chromatography (HPLC) with a UV detection and allowed the determination of the active sites. This work shows the potential effeciency of plasma technology in the industrial production of functionalized affinity chromatography solid supports useful for the covalent immobilization of biomolecules in several formats: membranes and beads.
2:15 PM Y2.2
THIN-FILM PLASMA DEPOSITION OF ALLYLAMINE; EFFECTS OF SOLVENT TREATMENT. M.T. van Os , B. Menges, R. Förch, W. Knoll, Max-Planck-Inst for Polymer Research, Materials Research Group, Mainz, GERMANY; R.B. Timmons, Univ of Texas at Arlington, Dept of Chemistry and Biochemistry, Arlington, Texas; G.J. Vancso, Univ of Twente, Dept of Chemical Technology, Enschede, THE NETHERLANDS.
Amine-functionalized thin films were prepared for subsequent grafting reactions and biomedical applications by plasma induced deposition of allylamine. Radio frequency (RF) plasma polymerization was carried out under both continuous wave (CW) and pulsed plasma conditions to control the film chemistry, all other process variables being held constant. Using plasma polymerized films for subsequent grafting reactions or for biomedical applications usually involves exposure of the films to a solvent environment. It was the major focus of this work to investigate both the chemical and physical effects of solvents on plasma polymerized allylamine films. Film properties were determined using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Photoelectron Spectroscopy (XPS), Waveguide Mode Spectroscopy (WaMS) and Surface Plasmon Spectroscopy (SPS). WaMS provided an ideal opportunity to study the complex swelling and drying behaviour of these films by allowing a simultaneous study of the changes in film thickness and refractive index. Although the amine groups of the monomer were increasingly retained in the films as the RF duty cycle was lowered, a larger amount of oxygen was also found to be incorporated upon exposure to air. Extraction in ethanol led to a decrease in film thickness, especially for the films produced at low duty cycles, but appeared to have little effect on the film composition, as measured by XPS and FTIR.
2:30 PM *Y2.3
RF PLASMA-DEPOSITION OF Ag-CONTAINING PEO-LIKE COATINGS. Pietro Favia , Michele Vulpio, Rosamaria Marino, Riccardo d'Agostino, Rogerio Pinto Mota* Department of Chemistry, University of Bari, Dept of Chemistry, Bari, ITALY; * Department of Physics and Chemistry, Guaratinguet, BRASIL.
Metal-containing organic coatings can be deposited in RF Glow Discharges fed with organic monomers, where the coating originated from the monomer is co-deposited with the metal coming from a sputtering or an evaporation source, or from an organometallic compound. Different composite coatings have been obtained with this approach, including Au/teflon-like, Au/silicone-like films and Ag/DLC. Polyethyleneoxide(PEO)-like films are interesting as bacterial resistant coatings for biomedical devices, since they probably merge the non fouling properties of PEO and PEO-like films with the anti-bacterial properties of silver. Ag/PEO-like films were deposited in Glow Discharges fed with vapors of diethyleneglycol-dimethylether and argon, in an asimmetric RF parallel-plate reactor. Proper experimental conditions were utilized for limiting the monomer fragmentation in the glow and, at the same time, sputtering Ag from the silver RF cathode. Ag-containing films of CxHyOz composition, variable PEO nature and Ag content were deposited at the ground electrode of the reactor. The presence of silver and DEGDME fragments in the discharge was checked through Optical Emission Spectroscopy; CH, CO, H, Ar and Ag species were detected. The surface composition of the films was investigated with ESCA and Water Contact Angle measurements. An interesting correlation was found between the corrected emission intensity ratio IAgPAr/IAr of silver atoms and the film Ag content measured by ESCA, which could be utilized as in situ diagnostic control tool of the process.
SESSION Y3: FUNDAMENTALS OF PLASMA PROCESSING
Chair: Michael R. Wertheimer
Monday Afternoon, November 30, 1998
Essex Center (W)
3:30 PM Y3.1
GAS PHASE AND PARTICLE DIAGNOSTIC OF HMDSO PLASMAS BY INFRARED ABSORPTION SPECTROSCOPY. C. Courteille, D. Magni, Ch. Deschenaux, A.A. Howling, Ch. Hollenstein, Centre de Recherche en Physique des Plasmas, EPFL, SWITZERLAND; P. Fayet , Tetra Pak, Plasma Technology, SWITZERLAND.
Plasma assisted processes for the deposition of silicon dioxide are widely used in industry. Practical and robust plasma diagnostic methods are strongly required to understand the ongoing plasma physical and plasma chemical phenomena and to optimized deposition and its functionality.