Academic literature on the topic 'Piranha (H2O2:H2SO4)'

In this paper, silicon direct bonding was performed by two different cleaning processes, and the bonding quality was obtained by tensile test and IR test. For (100) P-type double side polished wafer, the optimum process condition was established with respect to the results of two different cleaning processes. The cleaning process of NH3•H2O/H2O2/H2O (Standard Cleaning 1, SC1) after the H2SO4/H2O2 (piranha solution) was found to be better suited for high bonding quality. The bonding strength of the SC1-cleaned samples is about 5.4 MPa with partially crack but no more than 0.7 MPa for the only piranha solution cleaned samples.

In this paper, the low-temperature (less than or equal to 400 °C) silicon wafer direct bonding technology using wet chemical surface treatment is proposed. For bonded pairs of silicon-oxide-covered wafers, the optimum process condition is established with respect to the experimental results of two different wet chemical processing methods. The bonding quality is evaluated through infrared transmission test and tensile test. Experimental results indicate that the bonding strength of the additional 29% NH3•H2O treated samples is about 7.2 MPa, while it is no more than 3.1 MPa for the only piranha (H2SO4/H2O2) solution and RCA1 (NH3•H2O/H2O2/H2O) solution cleaned samples. Effect of the pulling speed on tensile test is also investigated. The results show that the pulling speed effect should be considered during the tensile test.

This paper describes a new fabrication technique for RF MEMS switches where the coplanar waveguide (CPW) is fabricated in a basin. A planar profile and good coverage at the edges in a basin is achieved by spinning and baking the sacrificial positive photoresist (PPR) in multiple steps to fill the basin. The basin structure allows an increase in the length of the membrane resulting in lower pull-in voltage and better isolation. The PPR is removed using Piranha solution (H2SO4:H2O2::3:1). Structures with the gap of about 2.5 µm and the thickness of the gold membrane varying from 1µm to 2.5 µm have been successfully realized.

Twenty years ago dissolved ozone in DIW (DiO3) found its way into the semiconductor industry as a cleaning agent. DiO3 provides an effective replacement for Piranha (H2SO4, H2O2) cleans. The fundamental chemistry of ozone based cleaning is due to direct and indirect reactions of ozone and oxygen radicals (the so-called radical pathway). Due to its high oxidation rate the radical pathway can accelerate the reaction. Megasonic energy can act as an initiator for the radical pathway. At the same time, due to the creation of turbulence inside the boundary layer, the available ozone close to the surface is increased. In the present study this chemical physical combination was tested for improvement of photoresist strip rate.

AbstractCombinatorial methods were used for studying dewetting of thin hydrophobic polystyrene (PS) and hydrophilic poly(DL-lactic acid) (PDLA) films on chemically modified gradient energy surfaces. Substrate libraries were prepared by immersing passivated Si (Si-H surface functionality) in Piranha solution (H2SO4/H2O2/H2O) at acontrolled rate, yielding a systematic variation of solvent contact angles across the surface. Additionally, chlorosilane-treated Si surfaces were exposed to UV radiation in a gradient fashion under ozone atmosphere such that a range from hydrophobic to hydrophilic conditions was obtained across the surface (≈ 3 cm). Solvent droplet contact angles of water and diiodo methane were used to quantify the spatial variation of surface energy along one axis across the surface. Libraries of thin films of PS or PDLA coatings on gradient energy surfaces orthogonal to gradients in film thickness were screened for dewetting behavior using automated optical microscopy. Contrasting trends in the wettability of PS and PDLA were visibly apparent as a function of surface energy of the substrate. The number density of polygons of the dewet PS films was found to obey a power law relationship with both film thickness and substrate surface hydrophilicity.

ABSTRACTSi surface cleaning has been studied intensively in these days. One of the major concerns is about the removal of metallic impurities on Si surface. In this study we choose contaminant element of Cu which shows high electronegativity value compared to Si's. The Si substrate was cleaned with using piranha (H2SO4:H2O2=4:1) and HF (HF:H2O=1:100) solutions to eliminate the organic impurities and native oxide. The initial Si substrate was then contaminated intentionally by dipping into the 1 ppm standard solution of Cu and cleaned by the cleaning splits of the chemical solution HF combined with UV/O3 treatment and the chemical mixture of H2O2 and HF. The initial substrates which were contaminated with the standard Cu solution exhibited the contamination levels of 1013–1015 atoms/cm2 and these substrates were cleaned and showed Cu concentration down to the levels as lower as 1010 atom/cm2 which were monitored by TXRF (total reflection X-ray fluorescence). And repeated treatments of these cleaning splits improved the surface microroughness of these initial substrate which were measured by AFM (atomic force microscope). The surface and interface morphologies contaminated with Cu were examined by SEM (scanning electron microscope) and TEM (transmission electron microscope). It was observed that Cu impurities were adsorbed on Si surface not in a thin film but in a particle form as a hemispherical shape. The chemical composition of Cu impurities and interface between Cu and Si substrate was investigated by AES (Auger electron spectroscope). The result exhibited that Cu element adsorbed on Si surface by chemical adsorption and this resulted in oxidation of Si substrate.

This dissertation outlines the research and development of ground-breaking nanometer sized openings (nanopores) integrated with an on-chip optofluidic platform. This platform represents a significant advancement for single nanoparticle sensing. In this work specifically, the integrated optofluidic platform has been used to electrically and optically filter and detect single nanoparticles using ionic current blockade and fluorescence experiments. The correlation of electrical and optical signal has provided the highest sensitivity single nanoparticle measurements ever taken with integrated optofluidic platforms. The particular optofluidic platform used for this work is an antiresonant reflecting optical waveguide (ARROW). ARROW hollow and solid core waveguides are interference based waveguides that are designed to guide light in low index media such as liquids and gases. Because of this unique guiding property, ARROW hollow cores can be used to sense and analyze low concentrations of single particles. Additionally, because ARROW platforms are based upon standard silicon processing techniques and materials, they are miniature sized (~1 cm2), inexpensive, highly parallelizable, provide a high degree of design flexibility, and can be integrated with many different optical and electrical components and sources. Finally, because of the miniature, integrated nature of the ARROW platform, it has the potential to be incorporated into hand held devices that could provide quick, inexpensive, user-friendly diagnostics. The ARROW platform has been through many revisions in the past several years in an attempt to improve performance and functionality. Specifically, advanced fabrication techniques that have been used to decrease the production time, increase the yield, and improve the optical quality of ARROW platforms are discussed in the first part of this work. These advancements were all developed in order to facilitate the production of high quality integrated nanopores and ARROW platforms. The second part of this work then focuses on the actual integration of micrometer sized openings (micropores) and nanopores in the hollow waveguide section of ARROW platforms for filtering, detecting, and analyzing single nanoparticles. The successes and attempts at achieving these results are the basis of this dissertation of work.