The balance of power model is a relatively simple model, which determines the power dissipated both in the plasma bulk and in the plasma sheath, as well as the ion flux and the average energy lost by an electron in the plasma bulk. It requires only the measurement of the total power and the self bias voltage. The original model does not take into account the effect of the plasma potential on the energy of incoming ions, because for most plasmas, the plasma potential is negligible compared with the self bias voltage. In this work, the plasma potential was taken into account. For pure SF6 plasmas, the modification had a significant effect on the ion flux, which increased by more than a factor 2, when compared with the original model. Besides, there are strong indications that the silicon etching with SF6 was mostly determined by the plasma bulk power, but the contribution from ion bombardment was considerable, too. For less electronegative plasmas, the influence of the plasma potential may be neglected.

In this work inductively coupled argon plasmas, generated by an external coil, are studied in the low pressure range. The E mode to H mode transition is observed and analysed using the DC self bias potential and the luminous intensities of three argon spectral lines, measured by optical emission spectroscopy. According to our results, during the mode transition the electron density of the plasma suddenly increases, and the average electron energy is higher in the E mode than in the H mode.

From the Maxwell-Boltzmann electron energy distribution function in a glow discharge, the probability of an electron to reach a planar electrostatic probe introduced in a plasma chamber is calculated. Two models to account for the potential barrier between the probe and the plasma are used: a constant plasma potential and a sinusoidal plasma potential. The calculated results show great differences, hence one should consider the oscillations in the plasma potential in order to calculate, for instance, the electron temperature from an electron energy distribution function. One also may conclude that the probability an electron reaches the probe is small if the probe potential is sufficiently negative.

Vertical and horizontal etching of resist was investigated in order to propose modifications to the existing models of plasma etching of resist with oxygen plasmas. Ion bombardment proved to influence dramatically the vertical etch rate, while it also influenced the horizontal etch rate. The horizontal etch rate of a thin resist layer was higher than that of a thick resist layer. These observations are compatible with the model that free oxygen atoms may travel over relatively long distances over inorganic surfaces before binding themselves to the constituents of the resist. The model of adsorption-desorption, however, is not adequate.

Coulometric reduction (CR) has been widely used to study atmospheric copper corrosion and tarnishing phenomena and to measure the copper corrosion rate. To find other CR applications, this technique was used to study the reaction of copper electrodes with fluorine-containing plasmas used for silicon etching. Copper samples were submitted to SF6-plasma environments and the CR time of the chemical species formed over the surface was measured. The CR test was made using a fixed cathodic current density (0.05 mA/cm(2)) to obtain voltage-time data (E vs. t). Two plateaus, at around -550 and -750 mV, were found. The -550 mV plateau corresponds to Cu2O reduction. Additional CF4-plasma exposure tests and Rutherford backscattering spectroscopy analysis indicated that the -750 mV plateau corresponds to a Cu-F compound. Surprisingly no Cu2S was detected by CR. CR is a fast technique that proved to be useful in determining, in a qualitative way, chemical reactions that take place at the electrode surface in silicon-etching microelectronic processes. There must be further study of the potential of this technique as a quantitative tool. (C) 2003 The Electrochemical Society.

 A process for large-scale fabrication of an array of divergent cylindrical micro lenses is presented. The device was fabricated employing a silicon-based micromachined mould combined with a replication technique of PMMA spin casting and a suiting post baking cycle. The resulting device is capable to split an incoming laser beam at a high fan-out angle. Key-words  microlenses array, silicon-based micromould, polymer-based microlenses

The density of the stress current flowing through metal stripes for electromigration (EM) median time to failure (MTF) tests should vary as little as possible among all the structures under test. This paper proposes an alternative method to the procedure described in ASTM F 1260, to determine the stress currents for these tests, resulting in smaller stress current density differences among different test structures. This method uses the average resistivity of the metal film to calculate the stress current for each individual test structure. In the standard method (ASTM F 1260), the average film thickness is used to calculate the cross-sectional area, which is used to calculate the stress current. The resistivity of the deposited film (almost always) varies less over a wafer than the film thickness. The alternative method results in an improved precision of the stress current density. A comparison between the two methods is made and two experiments are used to illustrate the difference. For Al-1at.% Si layers deposited in our sputtering system, the precision of the stress current density is improved by a factor of three.

Due to decreasing in LSI, VLSI,(ULSI), dry etching steps (Plasma etch, RIE, RIBM...) replace most wet etchings. Initially, most of the attention was paid to patterning of silicon nitride and polysilicon (etching steep walls with no undercut.) Only during the last 2 years, dry etching of silicon dioxide became a hot topic. This paper gives a description of an integrated process for etching contact windows in silicon dioxide. Also basic mechanisms of the silicon dioxide etching are explainer.

The interest in new materials for photonic devices operating at infrared (IR) and visible (VIS) region has motivated the studies of glasses doped with rare-earth. We report blue cooperative luminescence properties for Yb 3+ -doped GeO2-PbO glasses. Luminescence and lifetime measurements in the VIS and near IR regions were performed to investigate the spectroscopic characteristics of the glasses. Intense emissions around 507 nm and 1010 nm were observed. The VIS lifetimes (~0.4 ms) are about half of their respective near infrared ones (~0.8 ms), as expected for materials in which the VIS emission is caused by the cooperative luminescence. The obtained results suggest this composition as potential material to be used in devices operating in the VIS spectral range, such as 3-D displays.