Pulsed metalorganic chemical vapor deposition (MOCVD) of conformal copperseed layers, for the electrodeposition Cu films, has been achieved by analternating supply of a Cu(I) source and H2 reactant at thedeposition temperatures of 50 - 100°C. The Cu thickness increasedproportionally to the number of cycle, and the growth rate was in the rangeof 3.5 to 8.2 A /cycle, showing the ability to control the nano-scalethickness. As-deposited films show highly smooth surfaces even for more than100nm. In addition, about a 90% step coverage was obtained inside trenches,with an aspect ratio greater than 30:1. H2, introduced as areactant gas, can play an active role in achieving highly conformalcoatings, with increased grain sizes.

The effect of Mg in Ag(Mg)/SiO2/Si multilayers on the adhesion, passivation, and resistivity following vacuum annealing at 200–500 °C has been investigated. The annealing of Ag(Mg)/SiO2/Si multilayers produced surface and interfacial MgO layers, resulting in a MgO/Ag/MgO/SiO2/Si structure. The formation of a surface MgO/Ag bilayer structure provided excellent passivation against air and CF4 plasma chemistry. In addition, the adhesion of Ag to SiO2 was improved due to the formation of an interfacial MgO layer resulting from the reaction of segregated Mg with SiO2. However, the negligible solubility of Si in Ag prevented the dissolution of free silicon into the Ag(Mg) film produced from the reaction Mg + SiO2 = MgO + free Si, which in turn limited the reaction between Mg and SiO2, which led to a decrease in the adhesion of Ag to SiO2 at the higher temperature. The use of an O2 plasma prior to Ag(Mg) alloy deposition on SiO2 produced an oxygen-rich surface on the SiO2, which allowed for the enhanced reaction of the segregated Mg and SiO2 at the surface, thus resulting in markedly increased adhesion properties.

The annealing of Ag(40 at.% Cu) alloy films deposited on a Si substrate at 200 – 800 oC in vacuum has been conducted to investigate the formation of Cu3Si at the Ag-Si interface and its effects on adhesion and resistivity of Ag(Cu)/Si structure. Auger electron spectroscopy(AES) analysis showed that annealing at 200°C allowed a diffusion of Cu to the Si surface, leading to the significant reduction in Cu concentration in Ag(Cu) film and thus causing a rapid drop in resistivity. In addition, the segregated Cu to the Si surface reacts with Si, forming a continuous copper silicide at the Ag(Cu)/Si interface, which can contribute to an enhanced adhesion of Ag(Cu)/Si annealed at 200 oC. However, as the temperature increases above 300°C, the adhesion tends to decrease, which may be attributed to the agglomeration of copper silicide beginning at around 300°C.

A self-aligned surface MgO layer was used as a mask for dry etching the Cu(Mg) alloy films using an O2 plasma and H(hfac) chemistry. The surface MgO layer was formed by diffusion of Mg from Cu film to the free surface. Cu(4.5at%Mg) film having thickness of 300nm was annealed in O2 ambient at 10 mTorr, 500°C for 30min, followed by the patterning of the MgO layer using photolithography and HF wet etch process. The patterned MgO layer successfully served as a hard mask for dry etching the Cu(Mg) alloy films with a taper slope. In addition, the high quality self-aligned MgO layer was formed upon annealing the Cu(4.5 at.% Mg) alloy films at the low temperature of 300°C. Furthermore, the surface MgO layer grown on Cu(2.3at.% Mg) alloy films at 500°C withstood as a hard mask for dry etching, and thus achieving the patterned copper alloy lines with the low resistivity of 2.2 μΩ-cm. Consequently, this novel etch process using a self-aligned MgO mask can be used for patterning the low resistivity copper alloy lines with a low thermal budget, which is suitable for large-size TFT-LCDs.

The effect of Mg in Ag(Mg)/SiO2/Si multilayers on adhesion, agglomeration, and resistivity after annealing in vacuum at 200 to 500 have been investigated. The annealing of Ag(Mg)/SiO2/Si multilayers produced surface and interfacial MgO layers, resulting in MgO/Ag(Mg)/MgO/SiO2/Si structure. The presence of surface MgO provided the passivation against air, thus leading to the significantly enhanced resistance to agglomeration. In addition, the resistivity of Ag(Mg) film decreased by lowering Mg content and increasing the annealing temperature as well. Furthermore, Ag adhesion to SiO2 was improved due to the formation of the interfacial MgO layer resulting from the reaction of segregated Mg with SiO2. Also, the negligible solubility of Si in Ag prevented the dissolution of free silicon produced from the reaction, Mg + SiO2 = MgO + Si, which was in contrast with the dissolution of a significant amount of silicon released from the SiO2 substrate in Cu(Mg)/SiO2/Si multilayers after annealing at high temperature, e.g., 400. The dissolved Si in Cu caused the rapid increase in resistivity in Cu(Mg)/SiO2/Si.

In this study, Ir/IrO2 mixture electrodes are fabricated by furnace oxidation of sputter deposited Ir, IrO2 and their hybrid electrodes. The characteristics of furnace oxidation of various electrode stems with Ir family and their limitation are investigated. Annealing at higher than 700°C oxidation results in formation of undesirable extrusions in Ir electrode. When the Ir oxide facet extrusions are formed, Ir near at the extrusion is used up and SiO2 substrate are exposed. In addition, furnace oxidized Ir/Ti electrode is suggested as an alternative electrode, which shows smooth surface, good thermal stability, high oxygen contents and low resistivity.