Mechanical Characterization of Multilayer Thin Film Stacks Containing Porous Silica Using Nanoindentation and the Finite Element Method

2005 ◽  
Vol 875 ◽  
Author(s):  
Ke Li ◽  
Subrahmanya Mudhivarthi ◽  
Sunil Saigal ◽  
Ashok Kumar

AbstractNovel metal/dielectric material combinations are becoming increasingly important for reducing the resistance-capacitance (RC) interconnection delay within integrated circuits (ICs) as the device dimensions shrink to the sub-micron scale. Copper (Cu) is the material of choice for metal interconnects and SiO2 (with a dielectric constant k = ∼ 3.9) has been used as an interlevel dielectric material in the industry. To meet the demands of the international road map for semiconductors, materials with a significantly lower dielectric constant are needed. In this study, the effects of porosity and layer thicknesses on the mechanical properties of a multilayer thin film (Cu, Ta and SiO2)-substrate (Si) system are examined using nanoindentation and finite element (FE) simulations. A micromechanics model is first developed to predict the stress-strain relation of the porous silica based on the homogenization method for composite materials. An FE model is then generated and validated to perform a parametric study on nanoindentation of the Cu/Ta/SiO2/Si system aiming to predict the mechanical properties of the multilayer film stack.

Vibration ◽  
2021 ◽  
Vol 4 (1) ◽  
pp. 151-174
Author(s):  
André F. S. Rodrigues ◽  
Zuzana Dimitrovová

In this paper, the three-layer model of ballasted railway track with discrete supports is analyzed to access its applicability. The model is referred as the discrete support model and abbreviated by DSM. For calibration, a 3D finite element (FE) model is created and validated by experiments. Formulas available in the literature are analyzed and new formulas for identifying parameters of the DSM are derived and validated over the range of typical track properties. These formulas are determined by fitting the results of the DSM to the 3D FE model using metaheuristic optimization. In addition, the range of applicability of the DSM is established. The new formulas are presented as a simple computational engineering tool, allowing one to calculate all the data needed for the DSM by adopting the geometrical and basic mechanical properties of the track. It is demonstrated that the currently available formulas have to be adapted to include inertial effects of the dynamically activated part of the foundation and that the contribution of the shear stiffness, being determined by ballast and foundation properties, is essential. Based on this conclusion, all similar models that neglect the shear resistance of the model and inertial properties of the foundation are unable to reproduce the deflection shape of the rail in a general way.


2003 ◽  
Vol 766 ◽  
Author(s):  
Jin-Heong Yim ◽  
Jung-Bae Kim ◽  
Hyun-Dam Jeong ◽  
Yi-Yeoul Lyu ◽  
Sang Kook Mah ◽  
...  

AbstractPorous low dielectric films containing nano pores (∼20Å) with low dielectric constant (<2.2), have been prepared by using various kinds of cyclodextrin derivatives as porogenic materials. The pore structure such as pore size and interconnectivity can be controlled by changing functional groups of the cyclodextrin derivatives. We found that mechanical properties of porous low-k thin film prepared with mCSSQ (modified cyclic silsesquioxane) precursor and cyclodextrin derivatives were correlated with the pore interconnection length. The longer the interconnection length of nanopores in the thin film, the worse the mechanical properties of the thin film (such as hardness and modulus) even though the pore diameter of the films were microporous (∼2nm).


1997 ◽  
Vol 476 ◽  
Author(s):  
P. H. Townsend ◽  
S. J. Martin ◽  
J. Godschalx ◽  
D. R. Romer ◽  
D. W. Smith ◽  
...  

AbstractA novel polymer has been developed for use as a thin film dielectric in the interconnect structure of high density integrated circuits. The coating is applied to the substrate as an oligomeric solution, SiLK*, using conventional spin coating equipment and produces highly uniform films after curing at 400 °C to 450 °C. The oligomeric solution, with a viscosity of ca. 30 cPs, is readily handled on standard thin film coating equipment. Polymerization does not require a catalyst. There is no water evolved during the polymerization. The resulting polymer network is an aromatic hydrocarbon with an isotropie structure and contains no fluorine.The properties of the cured films are designed to permit integration with current ILD processes. In particular, the rate of weight-loss during isothermal exposures at 450 °C is ca. 0.7 wt.%/hour. The dielectric constant of cured SiLK has been measured at 2.65. The refractive index in both the in-plane and out-of-plane directions is 1.63. The flow characteristics of SiLK lead to broad topographic planarization and permit the filling of gaps at least as narrow as 0.1 μm. The glass transition temperature for the fully cured film is greater than 490 °C. The coefficient of thermal expansivity is 66 ppm/°C below the glass transition temperature. The stress in fully cured films on Si wafers is ca. 60 MPa at room temperature. The fracture toughness measured on thin films is 0.62 MPa m ½. Thin coatings absorb less than 0.25 wt.% water when exposed to 80% relative humidity at room temperature.


2002 ◽  
Vol 716 ◽  
Author(s):  
Ilanit Fisher ◽  
Wayne D. Kaplan ◽  
Moshe Eizenberg ◽  
Michael Nault ◽  
Timothy Weidman

AbstractThe success of future gigascale integrated circuits (IC) chip technology depends critically upon the reduction of the interconnects RC delay time. This calls for the development of new low dielectric constant (low-k) insulators, and for work on their integration with lower resistivity copper metallization.A porous silica based film prepared by surfactant templated self-assembly spin-on deposition (SOD) is an attractive candidate as a low-k material. In this research we have studied the structure, chemical composition and bonding of the film and its interface with copper metallization. The decomposition and vaporization of the surfactant in the last step of film deposition resulted in a film with an amorphous structure, as determined by XRD and TEM analysis. Its high porosity (35-58%) was confirmed by XRR and RBS measurements. XPS analysis of the Si2p transition indicated three types of bonding: Si-O, O-Si-C and Si-C. The bonding characteristics were also investigated by FTIR analysis. The effect of a hydrogen plasma post-treatment process on the film topography and bonding was determined by AFM and XPS, respectively. It was found that direct H2 plasma exposure significantly affected the surface roughness of the film and type of chemical bonding. The structure and properties of various PECVD deposited capping layers were also studied, as was the interface between the porous dielectric and Ta, TaxN and Cu (PVD deposited films) after annealing at 200-700°C in vacuum environment for 30 min. At temperatures up to 500°C, no significant diffusion of Cu or Ta into the porous film was detected, as determined by RBS. No copper penetration was detected up to 700°C, according to AES and SIMS analysis. However, at 700°C copper dewetting occurred when it was deposited directly on the porous silica based film.


Author(s):  
Zhaohui Shan ◽  
Suresh K. Sitaraman

Titanium thin films have been widely used in microelectronics due to their good adhesion to substrates, such as Silicon wafer and Quartz. However, mechanical behavior of Titanium thin films has not been well characterized. This paper presents a methodology that combines the nanoindentation technique and finite element modeling to characterize the mechanical (elastic and plastic) properties of thin film with its application on Titanium thin film deposited on silicon substrate. The results show that the elastic properties (Young’s modulus) of the Titanium thin film does not change much from the bulk Titanium, and the plastic properties (yield stress and strain hardening exponent) of the Titanium thin film are higher than those of bulk Titanium. This method is also applicable for the study of mechanical properties of other thin films and small volume materials.


1999 ◽  
Vol 593 ◽  
Author(s):  
P.J. Wolff ◽  
B.N. Lucas ◽  
E.G. Herbert

ABSTRACTA commonly used technique to compute mechanical properties from indentation tests is the Oliver and Pharr method. Using dimensional analysis and finite element modeling, this paper investigates errors when the Oliver and Pharr method is used to compute thin film properties.


2012 ◽  
Vol 622-623 ◽  
pp. 897-900 ◽  
Author(s):  
Suryakanta Nayak ◽  
Tapan Kumar Chaki ◽  
Dipak Khastgir

Polymer-ceramic nanocomposites with controlled dielectric properties are prepared using poly(dimethylsiloxane) elastomer as base matrix and barium titanate as filler. Barium titanate (BaTiO3) used in this study is prepared by solid state reaction at high temperature. The effect of BaTiO3 nanoparticles on electrical and mechanical properties are extensively studied and found that dielectric constant of nanocomposites increases significantly with the increase in BaTiO3 concentration where as volume resistivity decreases continuously. Different mechanical properties are also studied for all the composites in order to find the effect of filler concentration. Morphology of the prepared BaTiO3 was studied by field emission scanning electron microscope (FESEM).


2013 ◽  
Vol 832 ◽  
pp. 310-315
Author(s):  
R. Ahmad ◽  
M.S. Shamsudin ◽  
M. Salina ◽  
S.M. Sanip ◽  
M. Rusop ◽  
...  

MgZnO thin films are proposed as a new dielectric material for 1 GHz monolithic microwave integrated circuit (MMIC) applications. The high permittivity of this material enables size reduction; furthermore this can be fabricated using a low cost processing method. In this work, MgZnO/Pt/Si thin films were synthesized using a sol-gel spin coating method. The samples were annealed at various temperatures with the effects on physical and electrical properties investigated at direct current (DC) and high frequencies. The physical properties of MgZnO thin film were analyzed using X-Ray diffraction, with the improvements shown in crystalline structure and grain size with increasing temperature up to 700 °C. DC resistivity of 77 Ωcm at higher annealing temperature obtained using a four point probe station. In order to prove the feasibility at high frequencies, a test structure consisting of a 50 Ω transmission line and capacitors with 50 × 50 μm electrode area were patterned on the films using electron beam lithography. The radio frequency (RF) properties were measured using aWiltron 37269Avector network analyzer andCascade Microtechon-wafer probes measured over a frequency range of 0.5 to 3 GHz. The dielectric constant, loss tangent and return loss, S11improve with the increment annealing temperature. The dielectric constant was found to be 18.8, with loss tangent of 0.02 at 1 GHz. These give a corresponding size reduction of ten times compared to conventional dielectrics, silicon nitride (Si3N4). These indicate that the material is suitable to be implemented as a new dielectric material for 1GHz MMIC applications.


1992 ◽  
Vol 7 (6) ◽  
pp. 1553-1563 ◽  
Author(s):  
Martha K. Small ◽  
W.D. Nix

Since its first application to thin films in the 1950's the bulge test has become a standard technique for measuring thin film mechanical properties. While the apparatus required for the test is simple, interpretation of the data is not. Failure to recognize this fact has led to inconsistencies in the reported values of properties obtained using the bulge test. For this reason we have used the finite element method to model the deformation behavior of a thin film in a bulge test for a variety of initial conditions and material properties. In this paper we will review several of the existing models for describing the deformation behavior of a circular thin film in a bulge test, and then analyze these models in light of the finite element results. The product of this work is a set of equations and procedures for analyzing bulge test data that will improve the accuracy and reliability of this technique.


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