Papers by Keyword: Selective Removal

Abstract: For technology nodes beyond 14nm silicon nitride spacer etching has become a major challenge. Conventional plasma etching techniques based on CHF₃/O₂ cannot achieve thorough nitride removal on horizontal surfaces without inducing either CD loss or Si/SiGe source/drain recess. This leads to either gate leakage increase or poor raised source/drain epitaxy. To overcome atomic scale control issues faced with continuous plasma processes, several techniques aiming at achieving atomic layer etching or thin layer etching were recently described [1]. An original etching approach has been reported which consists in modifying the silicon nitride through H₂ ion implantation by plasma (ICP or CCP) and then selectively removing the modified fraction of the layer thanks to chemical etching [2]. Layer modification depth is controlled thanks to plasma parameters (bias voltage and process time). This unconventional technique was demonstrated on 14nm FDSOI logic device and showed less than 1nm spacer CD loss, less than 0.6nm SiGe recess which enabled defect-free source/drain epitaxy [2]. Mechanisms for silicon nitride modifications and selective removal are discussed in this article by comparing downstream plasma, liquid-phase HF and gas-phase HF as removal techniques.

Abstract: In this research, an experimental apparatus that composed of adiabatic packed absorption and regeneration columns was established to simulate H2S removal process. The results show that the reaction between CO2 and MDEA can be regarded as a rapid pseudo-first-order reversible reaction and the CO2 absorption mainly is controlled by liquid film resistance while the reaction between H2S and MDEA are reversible instantaneous. For H2S absorption, it is mainly controlled by gas film resistance but the rate of liquid film resistance to the total resistance of H2S absorption was distributed from 25.7% (column bottom) to 12.6% (column up).

Abstract: This study presents a new modus of selective removal technology and an excimer assistance on TFT-LCD above the five generation used to carry out the selective removal of nanostructures layers from optoelectronic flat panel displays’ color filter surface as well as the complete removal from the substrate of the ITO thin-films, RGB layer or resin BM layer. Displays’ color filters are produced using optoelectronic semiconductor fabrication techniques though the low yield during production can still be improved. Through the precise removal process of chemical etching and excimer assistance, the selective removals of different layers on top of color filter substrates will cut down the production costs. It can individually pick out and remove defective films or directly remove all films but the Cr layer or bare glass. Experimental results point out defective ITO thin-films, RGB layers, or resin BM layer can now be recycled with great precision. When the ITO proves difficult to remove, excimer-light can also be used to help with its removal. During the color filter recycle process the use of a 172nm excimer-light can remove stubborn film residues, effectively improving the quality of recycled color filters. This study offers a recovery module for defective diaplays’ color filters can be reused and fed back into the color filter production line, therefore provides many benefits in the industry of optoelectronic semiconductor.

Abstract: Based on the principle of micro electrical discharge machining (EDM), a reversible machining method is proposed, which can achieve depositing or removing selectively metal material for the fabrication of micro structures. It is easy to transform the machining process from deposition to removal in one machining system. The characteristics of the deposited material show that the components of deposited material are almost the same as those of the tool electrode, and the metallurgical bonding has formed on the interface between the deposited material and the base. Moreover, the deposited material has well machinability in different micro EDM selective removal process, including micro EDM die-sinking and micro EDM milling. As a result, a micro square column with 0.1mm in side length, 0.88mm in height and a micro cylinder with 0.14mm in diameter, 1.18mm in height were fabricated by using the micro reversible EDM process.