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Free radicals from processing plasmas are known to cause damage to dielectric films used in semiconductor devices. Many radicals are highly reactive and can readily interact with the material exposed to the plasma. This can modify the chemical structure of the material causing deterioration of electrical and mechanical properties of the films. This work detects the transmission of oxygen radicals through single- and double-layer silicon-nitride and silicon-dioxide freestanding films. The films were exposed to oxygen plasma. A fluorophore dye was used to detect the oxygen radicals traversing through the films. By measuring the fluorescence of the dye before and after multiple timedplasma exposures, the transmission properties of oxygen radicals through the material were found. The results indicate that the absorption length of oxygen radicals increases with increasing plasma exposure times for Si3N4 films because the oxygen plasma oxidizes the top layer of the film and forms a less dense silicon oxynitride layer. For SiO2 films, the absorption length was found to decrease as a function of plasma exposure time because of oxidation of the SiO2 surface which leads to the formation of a denser oxide layer on the surface of the sample. [ABSTRACT FROM AUTHOR]

This paper reports on a micromachined Kelvin probe structure with an integrated scanning tip and an integrated electrothermal actuator that provides axial dithering motion. The device is fabricated from metal foil by a modified microelectrodischarge machining process that allows electrical isolation within the device. In particular, it permits the incorporation of a wide epoxy plug that creates an insulating gap with low parasitic capacitance between the probe and the actuator. The epoxy structures are found to withstand the thermal and mechanical conditions encountered during device operation. The device is used to measure changes in the external surface potential of a parylene microfluidic channel as a function of varying pH of liquid inside the channel. A contact potential difference of [approximately equal to] 6V is measured for a change in pH from 4 to 8 within the channel. The device is also used to map embedded charge in a thin Si[O.sub.2] layer on a Si substrate, showing it to be suitable for monitoring microelectronics manufacturing processes. [1072] Index Terms--Contact potential, oxide charge, pH, surface potential.

A hollow-cathode microplasma was used to modify the lumenal surface of small-diameter polyethylene (PE). We make use of two microplasma diagnostics to monitor the plasma properties during the treatment process. A microwave cavity was used to measure the density of the microplasma. Emitted light from the microplasma was fed into a monochromator at various positions along the PE tube to assess uniformity of the microplasma. Effectiveness of plasma treatments were evaluated using the capillary-rise method at various positions along the tubing. We show a correlation between the properties of the inner surface of the PE tubing and the light emitted from the plasma. A Poly(ethylene oxide) (PEO) surfactant was immobilized to the lumenal surface of the PE tubing using the microplasma discharge. An in vitro blood-circulation loop was constructed to test the hematocompatibility of the PE tubes. After blood exposure, scanning electron microscope images were taken to assess the density of adhering platelets along the length of the tubes. The plasma-treated tubing showed fewer blood adherents than the untreated tubing. By suitably controlling the pressure drop along the tube, the uniformity of the microplasma treatment along the tubing can be optimized. Index Terms--Argon plasma immobilization, biomaterials, blood, capillary rise method, hematocompatibility, hollow cathode discharges, microplasma diagnostics, microplasma surface modification, microwave cavity, polyethylene oxide (PEO), small-diameter polymer tubing, vascular grafts.

A study was conducted to analyze the silicon atom densities in silane/oxygen and tetrathoxysilane/oxygen electron cyclotron resonance plasma as functions of microwave power, pressure and gas flow rates. Measurements were carried out using an atomic absorption spectrometer with a silicon hollow-cathode lamp. Experimental results indicated high concentrations of silicon that can support a major portion of the film growth in the silane based chemistry.

A numerical code is developed to study the effect of ion density and temperature (as well as ion pressure and temperature gradients) on the amplitude of the local maxima of the poloidal viscosity with respect to the poloidal Mach number using the model developed by Shaing [1]. The sum of the poloidal viscosity and ion-neutral collisions is determined from the dependence of the plasma radial current on the radial electric field in a biased electrode experiment. The experimental results in the interchangeable module stellarator agree qualitatively with the predictions of the numerical calculation regarding the effects of variation of ion density and temperature on viscosity. Index Terms - Biased electrode experiments, L-H transition, stellarators, viscosity.

Numerical calculations based on Shaing's L-H transition theory in stellarators and performed by Dahi et al. determine viscosity as a function of ion flow speed in the interchangeable module stellarator (IMS). The calculations predict local maximums in viscosity at flows corresponding to Mach numbers -2 and -10, but not elsewhere. The local peaks manifest themselves as jumps in flow speed, and as regions of high radial electric field ([E.sub.r]) shear. By inducting flows swept between Mach numbers [+ or -]5, an electron injection biasing probe revealed a jump at -2, but none at +2, in agreement with the numerical results. A series of flow profiles at constant bias confirmed this result. Altogether, these data agree well with the numerical calculations and provide support for Shaing's L-H transition model as applied to stellarators.

Electron energy and electron density distributions of inductively coupled plasma source range from 1 to 2ev and 10 to the power of 10 to 10 to the power of 12 centimeters cubed, respectively, for rf powers between 100 and 500 W. Spatial profiles of the electron properties in organs from radio-frequency filtered Langmuir probes reveal the presence of cold electrons in the peak electron density well. High average energy values occur at strong rf electric field locations.

The effects of plasma exposure and vacuum-ultraviolet (VUV) irradiation on the mechanical properties of low-k porous organosilicate glass (SiCOH) dielectric films were investigated. Nanoindentation measurements were made on SiCOH films before and after exposure to an electron-cyclotron-resonance plasma or a monochromatic synchrotron VUV beam, to determine the changes of film hardness, elastic modulus, and crack threshold due to these exposures. This permits the effects of ion bombardment and photon bombardment to be analyzed separately. The role of energetic ions was examined with a variety of inert plasma-exposure conditions. The role of VUV photons was analyzed as a function of synchrotron photon energy. It was found that both energetic ions and VUV photons with energies larger than the bond energy of the Si-O bond cause a significant increase in film hardness along with a smaller increase in elastic modulus and crack threshold. Differential Fourier transform infrared spectra and x-ray photoemission spectroscopy results show that the energetic ions affect the SiCOH properties mainly through physical bombardment, during which the ions transfer their momentum to the Si-O-Si backbone and transform them into more energetically stable Si-O-Si network structures. This results in the Si-O-Si network structures becoming densified. VUV photons assist reaction that increase the number of bridging O3=Si-O-Si=O3 bonds and deplete nonbridging O3=Si-O and C-Si=O3 bonds. This increased degree of cross linking in porous organosilicate dielectrics can substantially enhance their hardness and elastic modulus while showing no significant film shrinkage or densification. [ABSTRACT FROM AUTHOR]

In this work, experimental measurements of the electronic band gap of low-k organosilicate dielectrics will be presented and discussed. The measurement of bandgap energies of organosilicates will be made by examining the onset of inelastic energy loss in core-level atomic spectra using X-ray photoelectron spectroscopy. This energy serves as a reference point from which many other facets of the material can be understood, such as the location and presence of defect states in the bulk or at the interface. A comparison with other measurement techniques reported in the literature is presented. [ABSTRACT FROM AUTHOR]

The effects of plasma exposure and vacuum-ultraviolet (VUV) irradiation on photopatternable low-k (PPLK) dielectric materials are investigated. In order to examine these effects, current-voltage measurements were made on PPLK materials before and after exposure to a variety of inert plasma-exposure conditions. In order to examine the effects of photon irradiation alone, PPLK samples were also exposed to monochromatic synchrotron radiation with 10 eV photon energy. It was found that plasma exposure causes significant degradation in electrical characteristics, resulting in increased leakage-currents and decreased breakdown voltage. X-ray photoelectron spectroscopy measurements also show appreciable carbon loss near the sample surface after plasma exposure. Conversely, VUV exposure was found to increase breakdown voltage and reduce leakage-current magnitudes. [ABSTRACT FROM AUTHOR]

Water uptake in porous low-k dielectrics has become a significant challenge for both back-end-of-line integration and circuit reliability. The influence of absorbed water on the mechanical properties of plasma-enhanced chemical-vapor-deposited organosilicate glasses (SiCOH) was investigated with nanoindentation. The roles of physisorbed (α-bonded) and chemisorbed (β-bonded) water were examined separately through annealing at different temperatures. Nanoindentation measurements were performed on dehydrated organosilicate glass during exposure to varying humidity conditions. The elastic modulus and hardness for as-deposited SiCOH are intimately linked to the nature and concentration of the absorbed water in the dielectric. Under mild-annealing conditions, the water-related film mechanical property changes were shown to be reversible. The mechanical properties of UV-cured SiCOH were also shown to depend on absorbed water, but to a lesser extent because UV curing depopulates the hydrophilic chemical groups in SiCOH. High-load indentation tests showed that in-diffusion of water in the film/substrate interface can degrade the hardness of SiCOH/Si film stacks significantly, while not significantly changing the elastic modulus. [ABSTRACT FROM AUTHOR]