The plasma-based etching processes of copper (Cu) and titanium tungsten (TiW) thin films, and the electromigration of the copper lines patterned by above etching processes were studied. Instead of vaporizing the plasma/copper reaction product, a dilute hydrogen chloride solution was used to dissolve the nonvolatile reaction product. The plasma/copper reaction process was affected by many factors including the microstructure of the copper film and the plasma conditions. Under the same chlorine plasma exposure condition, the copper conversation rate and the copper chloride (CuClx) formation rate increased monotonically with the Cu grain size. The characteristics of the Cu etching process were explained by diffusion mechanisms of Cl and Cu in the plasmacopper reaction process as well as microstructures of Cu and CuClx. The Cu chlorination process was also affected by the additive gas in the Cl2 plasma. The additive gas, such as Ar, N2, and CF4, dramatically changed the plasma phase chemistry, i.e., the Cl concentration, and the ion bombardment energy, which resulted in changes of the Cu chlorination rate and the sidewall roughness. TiW thin films, used as the diffusion barrier layer for the Cu film, were reactive ion etched with CF4/O2, CF4/Cl2, and CF4/HCl plasma. Process parameter such as feed gas composition, RF power, and plasma pressure showed tremendous effects on the etch rate and the etch selectivity. The TiW etch rate was a function of the sum of Cl and F concentrations and the ion bombardment energy. Cu/diffusion barrier metal stack was successfully patterned by above plasma etch processes. The electromigration (EM) performance of the Cu lines was evaluated by the accelerated isothermal test. The activation energy of 0.5~0.6 eV and the current density exponent of 2.7 were obtained. Failure analysis showed that both copper-silicon nitride cap layer interface and the copper grain boundary were active diffusion paths. The EM induced stress caused the cap layer crack and affected the reliability of Cu lines. The processes studied in this dissertation can be applied in advanced microelectronic fabrication including large area flexible microelectronics.

No description available.

This thesis is about thermal etching of quartz single crystals with boron oxide melt and thermal etchings on inorganic polymeric single crystals of orthosilicates, willemite (Zn2SiO4) and phenakite (Be2SiO4), where isolated [SiO4] groups are polymerized by corner-sharing with other tetrahedral groups, such as [ZnO4] and [BeO4]. On the thermal etching of quartz, experiments were performed on quartz (10 0), (0001), (10 1) and (11 1) from 500¢J to 700¢J. Three types of etch figures were recognized by scanning electron microscopy: isolated dislocation etch pit, aligned etch pits and flat etch pits. The effects of defect specification and £\-£] displacive phase transformation of quartz on its development of thermal etch figures were evaluated. By doing so, boron oxide melt was proved to be a useful etchant on the studies of defect types and dynamics of quartz. As for the thermal etching of phenakite type silicate, we conducted thermal-cycle etching of willemite at 1250¢J, hydrochloric and hydrofluoric acid etchings of willemite and phenakite at room temperature, and boron oxide melt etching of willemite and phenakite at 700¢J. Surface premelting, anisotropic lattice etching and defect etching were found to play important roles on the thermal etching of willemite. Impurity segregation at dislocation outcrops on willemite (0001) should occur in the first thermal cycling in order to nucleate hillocks at the centers of the hexagonal dislocation etch pits. Reflection IR spectroscopic analysis indicated the surface premelt has the same structural units as willemite, although the subsequent crystallization follows a silica rich path. A silica-rich surface coverage impedes the etching of crystal plane underneath. There is significant polygonization and cleaving-healing of willemite single crystal upon thermal cycling according to transmission electron microscopy observation. Phenakite has remarkable chemical and thermal etching resistance in comparison to its isostructure willemite due to site energy difference of Be and Zn in coordination number 4.

SiC etch development has been performed in a Lam TCP 9400SE II system (a system meant for polysilicon etching and modified for SiC etching). SiC etching has never been reported in this particular system. Various parameters (carrier material, pressure, gas additives, gas flow, and electrode power) were examined and their effects determined on etch rate and resulting surface morphology. An efficient carrier material (graphite), operating pressure (25 mTorr), and gas flow rate (30 sccm) for obtaining peak etch rates were determined for this system. Peak etch rates of 1254 Å/min. in CHF3:O2, 4314 Å/min. in SF6:O2, and 1255 Å/min. in NF3:O2 plasmas were obtained at 25 mTorr with 60%, 20%, and 30% O2 concentrations, respectively, and 1978 Å/min. in a NF3:Ar plasma with 10% Ar concentration. Gas additives were determined to have little or no effect in enhancing the etch rate at low pressures (2 mTorr). The addition of H2 in CHF3 plasmas resulted in severe polymerization when the concentration of H2 was 60% or greater. Increased bottom electrode power resulted in higher etch rates and more anisotropic etch profiles.

The purpose of this study was to compare the shear bond strength of orthodontic brackets to enamel in four bonding protocols: SEP without prior pumicing (None), Pre-etch and SEP without prior pumicing (Pre-etch), control: SEP with prior pumicing (Pumice), and Pre-etch and SEP with prior pumicing (Both). 80 extracted bovine incisors were randomly divided into 4 groups of 20, and brackets were bonded under the different experimental conditions. Debonding force was measured with an Instron universal testing machine. A two-way ANOVA comparing the four groups indicated that there was a significant difference in debonding force (P = 0.001). The SEP without prior pumicing group (17.69 ± 7.18 MPa) was statistically different from the SEP group with prior pumicing (25.82 ± 6.84 MPa). There was no statistical difference found among the other groups. Differences in the Adhesive Remnant Index (ARI) were analyzed by chi-square. ARI scores differed significantly (P =0.0048).

Die vorliegende klinische Studie verfolgte das Ziel das Universaladhäsiv 3MTM ScotchbondTM Universal (SBU) klinisch (FDI-Kriterien) und mit quantitativer Füllungsrandanalyse (QRA) über einen Zeitraum von 36 Monaten zu evaluieren und die beiden Analysemethoden miteinander zu vergleichen. Bei 22 Patienten wurden je 4 nichtkariöse zervikale Zahnhalsdefekte (NCCL) plastisch mit dem Komposit Filtek™ Supreme XTE restauriert. Das Universaladhäsiv 3MTM ScotchbondTM wurde in den drei Konditionierungsmodi self-etch (SE), selectiveenamel-etch (SEE) und etch-and-rinse (ER) angewendet. Als Referenzstandard diente das Etch-and-Rinse-Adhäsiv OptiBond™ FL (OFL). Die Füllungen wurden nach 14 Tagen (t1, Baseline), sechs Monaten (t2), zwölf Monaten (t3), 24 Monaten (t4) und 36 Monaten (t5) klinisch bewertet und parallel zur Herstellung von Repliken abgeformt. Nach 36 Monaten wurden aus den 22 Patienten 11 Patienten für die quantitative Füllungsrandanalyse (QRA) zufällig ausgewählt. Die Gruppenvergleiche erfolgten mit dem McNemar- (Klinik) und dem Friedman-/Wilcoxon-Test (QRA). Klinisch wurde ab dem sechsten Monat (t2) und zu jedem weiterem nachfolgenden Kontrollzeitpunkt (t3-t5) eine höhere kumulative Fehlerrate in der Kontrollgruppe OFL (23,8 %), als in den Gruppen SBU-SE (4,8 %), SBU-ER (0 %) und SBU-SEE (0 %) festgestellt. Bereits 14 Tage nach Füllungslegung (t1) wurden in den SBU-Gruppen weniger marginale Spaltformationen nachgewiesen als in der Kontrolle. Nach sechs Monaten (t2) wies die SBU-SE-Gruppe den größten Anteil an Randspalten aller Gruppen auf. Insgesamt zeigen in den SBU-Gruppen im Vergleich zu den OFL-Füllungen sowohl die klinischen als auch die QRA-Parameter ein geringeres Verbundversagen an der Zahnhartsubstanz-Komposit-Grenze an. Eine Unterscheidung zwischen Schmelz, Dentin und Zement konnte mittels QRA nicht getroffen werden. Sowohl bei den klinischen als auch bei den QRA-Parametern treten signifikante Gruppenunterschiede erstmalig nach sechs Monaten auf. Allerdings wurde bei der QRA ein Trend bereits 14 Tage nach Füllungslegung deutlich. Demzufolge lieferte die QRA trotz der kleineren Kohorte (n = 11) diese Gruppenunterschiede früher als die Bewertung mit klinischen Kriterien (n = 22). Zusammenfassend zeigte die QRA eine höhere Sensitivität und Reliabilität als die Betrachtung mit klinischen Parametern und ermöglichte eine frühzeitigere Aussage zur klinischen Bewährung von Adhäsivsystemen.:Inhaltsverzeichnis Kurzreferat II Abkürzungsverzeichnis III 1. Einführung in die Thematik 1 1.1. Adhäsivsysteme 1 1.2. Bewertungsmethoden zur Untersuchung des Adhäsivverbundes 3 1.3. Quantitative Randanalyse mit dem Rasterelektronenmikroskop 4 2. Zielsetzung und Arbeitshypothesen 9 3. Publikationsmanuskript 10 4. Zusammenfassung 35 5. Literatur IV 6. Darstellung des eigenen Beitrags XI Selbstständigkeitserklärung XIII

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FIB is currently the economic methods to produce nano-structure below 100nm. In the past, FIB manufactures nano-structure patterns also unsatisfactory. In this study, the influence of twice deposited mask layer on the aspect ratio of nano-structure and verticality of side wall contour was discussed. The single mask layer is used for pattern transfer. Pattern distortion may occur during etching due to several factors like improper parameter setting, limitation of machine table, etc. The most common situations are aciculate and salient shape on the top and angle of slope which is too big to be vertical. In order to improve above-mentioned situations, a mask layer of multi-deposition was designed to protect the side wall so that it could retard etching. In addition to modifying verticality of side wall, the aspect ratio could be raised indirectly because the second deposition had reduced the interval between patterns. In the aspect of using machine table, the first mask layer, chromium, which was deposited by the sputtering machine. And the etching pattern was directly written on the first mask layer by focused ion beam. The silicon was uncovered at etched place, and then the second mask layer, silica (SiO2), which was deposited by the sputtering machine. The surface contour was directly covered with silica layer. Right after that, the top and bottom of silica were removed through vertical etching by inductively coupled plasma machine. The silica on the side wall of structure was retained to protect the side wall and raise aspect ratio. Eventually, the silicon was etched by the same way of inductively coupled plasma machine that it was researched on the difference in etching gas. And there was a comparison between chlorine and fluorine gases. After optimizing parameters, the nano-structure was made under 100nm.

Linux network application framework can help programmers developing network service applications on Linux. Programmers can concentrate on the business logic of applications, and do not have to care about network transmission and serialization between client and server. In addition, application¡¦s client and server can be implemented by different programming languages and communicate with each other according to the programming languages supported by framework. This paper chooses Thrift and Etch to be the topic of Linux network application framework, and introduces their interface definition language, serialization and network architecture. This paper also makes experiments on the implementation of MongoDB, choosing of serialization and situation of multiple clients to a single server to get the performances of two frameworks. In general, Thrift has richer features and slightly better performance than Etch.

No description available.