Byung-Hyuk Jun

Preparation of a-SiNx thin film with low hydrogen content by inductively coupled plasma enhanced chemical vapor deposition

Amorphous silicon nitride (a-SiN x ) thin films are deposited at low temperature by remote-type inductively coupled plasma enhanced chemical vapor deposition (ICP-CVD) using N 2 /SiH 4 gases as reactant gases to obtain low hydrogen content in the films. Refractive index, deposition rate, stoichiometry, hydrogen content, and hydrogen configuration in the films are analyzed with the varation of deposition parameters. As RF power and N 3 flow rate increase, refractive index decreases due to the decrease of Si/N ratio, total hydrogen content is constant with N-H changing hydrogen bond configurations (Si-H, N-H) reversely. However, as substrate temperature increases, refractive index increases due to the reduction of Si/N ratio, and total hydrogen content as well as both hydrogen bond configurations (Si-H, N-H) decrease. In remote-type ICP-CVD using N 2 /SiH 4 gases, N-rich a-SiN X films with low refractive index and density are deposited due to efficient dissociation of N 2 gas by high density plasma, and hydrogen content in the films is greatly reduced.

Titanium oxide film for the bottom antireflective layer in deep ultraviolet lithography

Titanium oxide thin film, fabricated with tetraisopropyltitanate and oxygen by electron cyclotron resonance-plasma-enhanced chemical vapor deposition, is investigated as a potential candidate for the antireflective layer in KrF excimer laser (248-nm) lithography. The oxygen flow-rate dependence of the optical properties such as the refractive index (n) and the extinction coefficient (k) of the film at the 248-nm wavelength has been characterized, and the films with the expected combinations of n and k values for the antireflective layer have been deposited. Simulation results indicate that reflectance values of less than 4% and as low as 1.2% can be reached at the interface between the photoresist and the film postulating the structures of the photoresist/300-A TiO(x) film/c-Si substrate and the W-Si substrate, respectively, by selected proper combinations of n and k values. Moreover the reflectance can be further reduced to almost zero by changing the film thickness. Thus it is found that titanium oxide thin films can be used as the bottom antireflective layer in KrF excimer laser lithography.

A comparative study on the properties of TiN films prepared by chemical vapor deposition enhanced by r.f. plasma and by electron cyclotron resonance plasma

Abstract TiN thin films were prepared by both r.f. plasma enhanced chemical vapor deposition (r.f.-PECVD) and electron cyclotron resonance plasma enhanced chemical vapor deposition (ECR-PECVD) using TiCl 4 , N 2 and H 2 as the reactants at various deposition temperatures. The effects of deposition temperature on the compositional ratio [N]/[Ti], impurity content, crystallinity, lattice parameter, grain size, deposition rate, resistivity and step coverage were studied. TiN films prepared by ECR-PECVD were highly crystallized at a low temperature of 350 °C, while TiN films prepared by r.f.-PECVD began to show obvious crystallinity above500 °C. TiN films deposited by ECR-PECVD at lowertemperatures had lower impurity contents and lowerresistivity than those deposited by r.f.-PECVD.

Composition, oxidation, and optical properties of fluorinated silicon nitride film by inductively coupled plasma enhanced chemical vapor deposition

Amorphous fluorinated silicon nitride films have been deposited with the variation of NF3 flow rate using SiH 4 ,N 2, Ar, and NF3 gases by inductively coupled plasma enhanced chemical vapor deposition for the first time, and the absolute composition, oxidation mechanism, and optical properties were investigated. The absolute composition including hydrogen was performed by means of elastic recoil detection time of flight. It was found that the oxygen and fluorine contents in the film dramatically increased, but the hydrogen content decreased to below 4 at.% as the NF3 flow rate increased. The oxidation mechanism could be explained in terms of the incorporation of the activated residual oxygen species in the chamber into the film with unstable open structure by the fluorine-added plasma. It was shown that the density and optical properties such as refractive index, absorption coefficient, and optical energy gap depended on the film composition. The variations of the above properties for fluorinated silicon nitride film could be interpreted by the contents of fluorine and oxygen with high electronegativity.

Dependence of the properties of (SrxTi1−x)O3 thin films deposited by plasma-enhanced metal–organic chemical vapor deposition on electron cyclotron resonance plasma

(SrxTi1−x)O3 (0.26≤x≤0.55) thin films were prepared on p-type Si (100) and Pt/SiO2/Si substrates. A stoichiometric perovskite SrTiO3 film with good thickness and composition uniformity was obtained on 4 inch wafer (±7% temperature uniformity) using electron cyclotron resonance (ECR) plasma which compensated for the substrate temperature difference. It was found that the activity of the precursors can be controlled by changing the ECR plasma power and O2-to-(Ar+O2) flow rate ratio. The deposition rate and the Sr-to-Ti composition ratio of the films were increased with the ECR plasma power and the O2-to-(Ar+O2) flow rate ratio of the ECR plasma, because the activation and decomposition of the source of strontium vapor are more easily affected by the ECR oxygen plasma power than those of the source of titanium vapor. The crystallinity and the orientation of the film were controlled by its Sr-to-Ti composition ratio and oxygen activity or oxygen partial pressure. The films showed a uniform and fine grain structure, and a Sr-to-Ti composition dependence.

Fluorinated silicon nitride film for the bottom antireflective layer in quarter micron optical lithography

Fluorinated silicon nitride thin film as a bottom antireflective layer (BARL) material, being suitable for line-patterning in KrF excimer laser (248 nm) lithography, has been studied by film fabrication/characterization and computer simulation. Three-dimensional reflectance simulation process suggests that the 0% reflectance between photoresist (PR) and BARL can be achieved by selecting proper combinations of film optical properties such as refractive index (n), extinction coefficient (k) and thickness (d). For the PR/300 A BARL/c-Si or PR/300 A BARL/W-Si structure at a wavelength of 248 nm, the simulation process reveals that nearly 0% reflectance could be obtained when the n and k values of the film are 2.109 and 0.68 or 2.052 and 0.592 respectively. The fluorinated silicon nitride films prepared by ICP enhanced CVD have been evaluated with the variations of flow rates under the two conditions of and 3:20 (sccm). The film n and k values at 248 nm vary in the ranges of 1.665 - 2.352 and 0.007 - 0.695 respectively, depending on gas flow ratio. As it is very sensitive to the film thickness, the reflectance could be reduced, using compoter simulation, to almost 0% by changing the film thickness. Furthermore, the ARL performance for line/space processed by the KrF excimer laser stepper and the stripping ability/selectivity show this material to be a superior candidate for deep-UV microlithography applications.

Characterization of a‐SiNx Thin Film Deposited By Inductively Coupled Plasma Enhanced Chemical Vapor Deposition

Silicon nitride thin films are deposited at low temperature using the inductively coupled plasma enhanced chemical vapor deposition.(ICP‐CVD) N 2 and SiH 4 gases are used as reactant gases for deposition of silicon nitride thin films with low hydrogen content. Composition, refractive index, and hydrogen content of the films were examined with variation of N 2 flow rate, RF power and substrate temperature. As N 2 flow rate and RF power increase and substrate temperature is lowered, N/Si ratio is reduced producing higher refractive index of the film. Hydrogen content of the films is calculated by FTIR spectroscopy and is much less than those of the films deposited by conventional PECVD using SiH 4 /N 2 gases since N 2 gas is used instead of NH 3 gas. Total hydrogen content is constant regardless of RF Power and N 2 flow rate. However, the hydrogen content decreases with increasing substrate temperature due to the release of hydrogen at high temperature.