Electron-density and electron energy distribution functions (EEDFs) are measured in a 20-cm-diam by 14-cm-long cylindrical, inductively coupled plasma source driven by fields from a planar, spiral coil at 13.6 MHz. Radio-frequency (r-f) -filtered Langmuir probes are used to obtain spatial profiles of electron population characteristics in argon at powers and pressures of interest for etching and plasma-assisted deposition (l-100 mT). Electron densities range from lOlo to 10" cm3 with lOO-500 W of rf power and peak on axis in the center of the cylindrical volume. The EEDFs show that the observed average electron energy varies by 1-2 eV spatially, with the highest values of average energy occurring at those regions of strongest rf electric field. The EEDF measurements also reveal a significant population of cold electrons trapped in a potential well at the location of peak electron density. From these spatial measurements, spatial estimates of conductivity and ionization rate are deduced.

Abstruct-Plasma-aided manufacturing is used for producing new materials with unusual and superior properties, for developing new chemical compounds and processes, for machining, and for altering and refining materials and surfaces. Plasmaaided manufacturing has direct applications to semiconductor fabrication, materials synthesis, welding, lighting, polymers, anticorrosion coatings, machine tools, metallurgy, electrical and electronics devices, hazardous waste removal, high-performance ceramics, and many other items in both the high-technology and the more traditional industries in the United States.

A hollow-cathode microplasma modified the lumenal surface of small-diameter polyethylene (PE) tubing. A microwave cavity diagnostic was used to measure the density of the microplasma. Plasma light output was observed with a monochromator at various positions along the PE tube to assess uniformity. Treatment effectiveness was evaluated by measuring the variation in capillary rise at various positions along the tubing. A correlation between the properties of the inner surface of the PE tubing and the emitted light intensity was found. A poly(ethylene oxide) surfactant was immobilized to the lumenal surface of the PE tubing with an argon microplasma discharge. To test hematocompatibility, an in vitro blood-flow loop circulated heparinized human blood through both a plasma-treated and -untreated PE tubes, simultaneously. After blood exposure, the tubes were examined with a scanning electron microscope to assess the density of adhering platelets along the length of the tubes. By modifying the plasma parameters, the uniformity of the microplasma treatment along the tubing can be optimized.

Ionized physical vapor deposition is a technique for sputtering metal into small trenches, by ionizing sputtered metal atoms so that their trajectories can be controlled by electric fields. To this date no one has quantified exactly what fraction of the metal vapor is ionized, although the trends of how ionization varies with input parameters is known. This article describes and demonstrates a new quartz crystal microbalance design, which can be used to measure the ionized metal flux fraction arriving at the substrate location. Instead of using grids to repel ions as similar devices do, this analyzer works by applying a voltage bias to the front surface of the crystal in order to repel ions. A magnetic field adjacent to the face limits electron current to the microbalance, minimizing its perturbation of the plasma. The measurement tool described in this article does not suffer from complications caused by placing grids in front of the monitor and is an attractive method for characterizing ionized physical vapor deposition systems. Ion and neutral metal fluxes as a function of ionizer power are presented for an argon/copper discharge.

Real-time etch rate of thin transparent films is determined within seconds by an in-situ two-color laser interferometer. The use of two colors improves the accuracy of the calculated rates, provides an absolute measure of film thickness for endpoint prediction, and differentiates between etching and deposition. The tool state parameters, rf power to the antenna and the wafer stage, gas pressure and flow rates, are computer controlled and monitored. Real-time etch rate characterization is obtained by monitoring the etch dependence on varying tool state parameters. The density of the etch radicals, chlorine and fluorine, is obtained with xenon and argon actinometry using optical emission and mass spectra. An etch rate model, based on the input power to the wafer stage and the relative density of the etch radicals, is used to develop a model-based real-time control algorithm. This algorithm has been used to control the etch rate of unpatterned polysilicon and SiO2.