The modern IC process consists of a 13-layer metallization stack. Critical dimensions are 30-40 nm at the M0-
M2 metal layers and due to barrier resistance and electromigration reasons, copper is not the perfect choice
nowadays. There are two main alternatives to copper on M0-M2 layers: cobalt and ruthenium. Return to the
subtractive scheme could be a powerful solution for future interconnects although the dry etching process of
the metal is required for it. In this paper, different approaches to plasma etching of cobalt are studied. CO- and
halogen-containing plasmas were considered. It seems that etching in CO-based plasma is inefficient. The rate
was only 2 nm/min in a wide temperature range. The low-temperature (60°C) process of the cobalt etching in
BCl3/Ar plasma was developed. The etching rate for the process was 50 nm/min. All of the considered
processes are found to be aggressive toward the mask.
In this work we report a new approach to the fabrication of metallic nanowire and nanonet structures on a-Si/SiO2/Si substrates by combine plasma etching processes. For the formation of Pt nanostructures we used a controlled two-step plasma etching in C4F8/Ar and SF6 plasma, which resulted in a self-formation of fluorocarbon nanowires and nanonets. Then, we used these nanostructures as nanoscale templates for 10 nm thin metallic nanowires, which were obtained with magnetron Pt film deposition, Ar plasma sputtering and Pt redeposition.
The results of investigation of the effect of ion-plasma treatment in Ar plasma with ion energies εi = 15-30 eV on residual stress in thin Cr films are presented. Mean stress depending on εi and treatment time t was determined using Xray diffractometry and test microbridges, stress gradient was determined using test microcantilevers. The Cr films initially had compressive stress and a positive value of the stress gradient that is they had greater compressive stress near the interface than near the surface. The treatments at εi = 15-25 eV, t = 15-45 min led to increase in compressive stress. The treatments of Cr films at εi = 25-30 eV, t = 60 min led to decrease of the initial compressive stress. The stress gradient after ion-plasma treatment at εi above 15 eV increased. The higher the ion energy or the longer the treatment time, the greater the value of the stress gradient.
Electrostatically actuated MEMS switch with the resistive contact is presented. Design of the switch includes the active contact breaking mechanism, which allows to detach the beam from the signal electrode in case of sticking. The mechanism is realized by the presence of two driving electrodes under the beam. The switch is fabricated by the surface micromachining. Finite element simulation and experimental investigation of the switch in a cold regime are performed.
Resonant properties of the three-layer metallic cantilevers with 40 nm thickness are investigated. Two types of the nanocantilevers were fabricated: Cr-Al-Cr and Ti-Al-Ti. Resonant frequencies of the nanocantilevers were determined from the experimentally obtained resonant curves. Cantilever oscillations were excited by the electric force, the registration of the cantilever motion was performed by the optical lever method. Dependencies of the first and the second resonant frequencies on the cantilever length and width were experimentally obtained. The experimental data analysis and the comparison with the theoretical predictions were performed. Relations between the cantilever resonance properties and its dimensions and material are discussed.
A MEMS capacitive-type sensor is basically an electrostatic transducer that depends on electrical energy in terms of constant voltage (voltage drive) or constant charge storage (current drive) to facilitate monitoring of capacitance change due to an external mechanical excitation, such as force, acoustical pressure or acceleration. Microfabricated cantilever beams are widely used in MEMS capacitive-type sensors as the sensing element1.
One such representative of movable microdevices are the surface micromachined mechanical resonators that come in many geometrical configurations, such as laterally movable comb resonators, laterally and vertically movable beam resonators, and torsional resonators. The successful design and fabrication of these devices requires computer-aided design _CAD_ simulation tools capable of accurately simulating the electromechanical performance of MEMS devices. Accurate simulations are critical for the expeditious development of commercial products at reasonable cost. All CAD simulation tools require accurate measurements to verify models and to provide the values of the constants used in the models. In particular, in the case of micromechanical resonators, it is challenging to determine the mechanical properties of both static and dynamic behaviors of such micromechanical resonators2,3. The testing of these movable structures is usually performed using electrostatic excitation and detection by capacitive, piezoresistive, and optical methods4.
This paper presents the design, fabrication and testing of capacitive aluminum resonator with various movable membrane geometries, fabricated with surface micromachining.
A direct writing system based on a pulsed N2 laser is presented. It allows to create continuous relief in a number of polymeric materials. Polymers are etched in air directly under the laser beam action. It is possible to make a computer controlling smooth relief with a depth more than 40 micrometers . High speed cylindrical lens has been fabricated in polyamide film to demonstrate the abilities of the system.
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