Luca Zanotti

Infrared study of Si-rich silicon oxide films deposited by plasma-enhanced chemical vapor deposition

A single chamber system for plasma-enhanced chemical vapor deposition was employed to deposit different films of SiOx:N,H with 0.85⩽x⩽1.91, which are studied here by Fourier transform infrared transmission spectroscopy. The sample composition was determined by Rutherford backscattering spectrometry, nuclear reaction, and elastic recoil detection analysis. Moreover, physical properties such as thickness uniformity, deposition rate, density, wet and dry etch rates, and stress are determined. A quantitative study of Si–OH, N–H, and Si–H bonds was performed and interpreted on the basis of the random bonding model; in addition, the presence of NH2, Si–O–Si, H2SiO2, and Si–N groups was detected. The effect of sample annealing at 600 and 900u2009°C was studied and two species of Si–H bonds were identified, one more stable and the other one easily releasable. A reordering effect of annealing was also detected as a reduction of the amorphous network stress and as the increase of the bond angle in the Si–O–Si groups up...

Thermal conductivity of SiO2 films by scanning thermal microscopy

Abstract In microelectronics the thermal conductivity of dielectric films such as SiO 2 is of concern because, as dimensions shrink, heat removal from devices becomes a critical problem. A scanning thermal microscope was used to image thermal properties of silicon dioxide films deposited on silicon by plasma enhanced chemical vapor deposition. Thermal conductivity as a function of the layer thickness, ranging 50–1000 nm was measured. To interpret the experimental thermal data, a model has been developed on the basis of previously published heat-transfer concepts. An intrinsic thermal conductivity of 1.31xa0±xa00.11 W/K/m was calculated independent of the thickness and a thermal resistance of (6.8xa0±xa00.35)xa0×xa010 −7 m 2 K/W was calculated at the interfaces.

SiH bonding configuration in SiOx: N,H films deposited by chemical vapor deposition

Abstract A detailed study performed by means of infrared spectroscopy on Siue5f8H stretching in silicon-rich silicon oxide films deposited by chemical vapor deposition is presented. The experimental spectra of as-deposited and annealed samples are interpreted on the basis of a generalization of the random bonding model. The results indicate that two kinds of Siue5f8H bonds exist, one much more stable than the other, whose properties depend on their nearest neighboring atoms.

Silicon oxynitride study by the tetrahedron model and by spectroscopic ellipsometry

Silicon oxynitride samples deposited by plasma-enhanced chemical vapour deposition are characterized by different techniques to obtain their stoichiometry and density. From these data and applying the tetrahedron model, the optical functions in the range from 0.23 to 0.90 μm are calculated and compared with the results of spectroscopic ellipsometry.

Hydrogen determination in Si‐rich oxide thin films

Quantitative in‐depth distribution of the elements contained in silicon‐rich oxide thin films deposited on single‐crystal silicon by low temperature plasma‐assisted deposition has been performed by a combination of various MeV ion beam techniques. The quantity of oxygen and nitrogen has been measured by nuclear reactions, the silicon content has been determined by Rutherford backscattering, and elastic recoil detection was used for hydrogen. All the samples contain not only Si and O, but also N and H, which are residuals from the reactions involved in the deposition process. We did find that the MeV beam used in the nuclear techniques can induce a process of hydrogen desorption, which causes the measured H content to be a function of the He dose received by the sample. This phenomenon, not previously reported, must be taken into account to give the correct H content. The study of the kinetics of the He‐induced hydrogen desorption has been used to correct the experimental data and to determine the original...

Optical characterization of oxynitride films in the visible-ultraviolet range

Oxynitride optical properties in the visible-ultraviolet spectral range are very interesting, due to their use in electronic device manufacturing. This paper presents spectra of refractive index and extinction coefficient of oxynitride films deposited on silicon with different composition, as derived from spectroscopic ellipsometry measurements on the basis of an effective medium approach. These data evidence the presence of a Si-rich layer on the oxynitride/silicon interface. Electronic polarizability and energy gap of all compounds were evaluated. Moreover, absolute reflectance of the samples was derived from optical functions and compared with the measured value.

Radiation enhanced transport of hydrogen in SiO2

Abstract 2.2 MeV 4He+ and 7 MeV 15N2+ ion beams have been used to investigate, by in situ measurements, the hydrogen desorption processes in SiO2 thin films deposited by plasma enhanced chemical vapor deposition (PECVD). An effective cross-section of 3 × 10−16 cm2 for He and 17 × 10−16 cm2 for N has been measured for the ion-thin-film interaction phenomena. The structure crystalline silicon/thermally grown SiO2/PECVD film has also been investigated for the hydrogen radiation-enhanced diffusion in thermally grown SiO2. The data are consistent with a diffusion process with a diffusion coefficient of (5.0 ± 0.5) × 10−26 cm2/ion from a constant source at a concentration C0 = (2.5 ± 0.2) × 1021 at/cm3.

Semi-integrated SOG/TEOS etchback process for multimetal submicron devices

A semi-integrated SOG/TEOS planarization process for intermetal dielectric (ILD) has been developed in the CVD cluster system Precision 5000 (Applied Materials). The process consists of SOG etch back performed in one chamber immediately followed by plasma TEOS deposition in another chamber of the system, to reduce particle contamination and moisture adsorption in the SOG film. The main goal of the work was to develop an etchback process with very low SOG/TEOS selectivity (i.e., 0.7:1) and good etch uniformity, suitable for VLSI planarization requirements. The results of the parametric process characterization performed with the CHF3/CF4/Ar chemistry and the very satisfactory defectivity levels obtained for interconnections and intermetal oxide, for contacts leakage and capacitor breakdown are reported. Special emphasis has been devoted to the study of the oxide interface after the etchback to correlate the probable surface modification to the `peeling effect evidenced on the TEOS film. The advantages of using Ar sputter to solve the adhesion problem are then discussed.

Packaging Trends and Technology in Wireless and SSD Applications

Hand-handled, wireless world represents the most challenging environment for package technology where all the system performances must be densely stacked. Chip scale package (CSP) is the generic term for packages approaching chip size, and the fine-pitch versions of BGA have become the most widely used kind of CSP for system miniaturization. With the introduction of the new feature, where heterogeneous semiconductor devices are stacked together within a single package working at extremely high frequencies, the package design in terms of system simulation – mechanical, electrical, and thermal – is becoming one of most important development activities for delivering robust system solutions. In this chapter, the package historical trends against the system evolution will be discussed, analyzing the principal integration challenging. Among them, this chapter will focus on thin die thickness trend, taking into account the new process technology and the related impact on the device characteristics. This is considered as one of the most important back-end technologies, enabling the new era of the package integration and miniaturization. New interconnection technologies among dies will also be reviewed and discussed by deeply analyzing the features of through silicon via process. This process will allow the new interconnection scheme for microelectronics for the next decade.

Chemical-bond analysis of hydrogen-rich silicon oxynitride

We present measurements of the infrared absorption of Si-H, N-H, N-H2, and Si-N bonds in silicon oxynitride films. The shift of the position of the absorption bands in the spectra of different samples is related to the atomic environment of the bonds in each film.