scholarly journals Near-Plastic Threshold Indentation and the Residual Stress in Thin Films

1996 ◽  
Vol 436 ◽  
Author(s):  
J. E. Houston ◽  
T. A. Michalske
Keyword(s):  
Residual Stress ◽  
Interfacial Adhesion ◽  
Maximum Shear Stress ◽  
Indentation Modulus ◽  
Film Properties ◽  
Nanomechanical Properties ◽  
Average Grain Size ◽  
Film Substrate ◽  
Substrate Surfaces ◽  
Interfacial Force

AbstractIn recent studies, we used the Interfacial Force Microscope in a nanoindenter mode to survey the nanomechanical properties of Au films grown on various substrates. Quantitative tabulations of the indentation modulus and the maximum shear stress at the plastic threshold showed consistent values over individual samples but a wide variation from substrate to substrate. These values were compared with film properties such as the surface roughness, average grain size and interfacial adhesion and no correlation was found. However, in a subsequent analysis of the the results, we found consistencies which support the integrity of the data and point to the fact that the results are sensitive to some property of the various film/substrate combinations. In the present paper, we discuss these consistencies and show recent measurements which strongly suggest that the property that is being probed is the residual stress in the films caused by their interaction with the substrate surfaces.

scholarly journals The Effect of Stress on the Nanomechanical Properties of Au Surfaces

1996 ◽  
Vol 440 ◽  
Author(s):  
J. E. Houston
Keyword(s):  
Thin Film ◽  
Residual Stress ◽  
Local Level ◽  
Maximum Shear Stress ◽  
Critical Role ◽  
Film Stress ◽  
Indentation Modulus ◽  
Nanomechanical Properties ◽  
Average Grain Size ◽  
Film Substrate

AbstractStress in thin films plays a critical role in many technologically important areas. The role is a beneficial one in strained layer superlattices where semiconductor electrical and optical properties can be tailored with film stress. On the negative side, residual stress in thin-film interconnects in microelectronics can lead to cracking and delamination. In spite of their importance, however, surface and thin-film stresses are difficult to measure and control, especially on a local level. In recent studies, we used the Interfacial Force Microscope (IFM) in a nanoindenter mode to survey the nanomechanical properties of Au films grown on various substrates. Quantitative tabulations of the indentation modulus and the maximum shear stress at the plastic threshold showed consistent values over individual samples but a wide variation from substrate to substrate. These values were compared with film properties such as surface roughness, average grain size and interfacial adhesion and no correlation was found. However, in a subsequent analysis of the results, we found consistencies which support the integrity of the data and point to the fact that the results are sensitive to some property of the various film/substrate combinations. In recent measurements on two of the original substrate materials we found a direct correlation between the nanomechanical values and the residual stress in the films, as measured globally by a wafer warping technique. In the present paper, we review these earlier results and show recent measurements dealing with stresses externally applied to the films which supports our earlier conclusion concerning the role of stress on our measurements. In addition, we present very recent results concerning morphological effects on nanomechanical properties which add additional support to the suggestion that near-threshold indentation holds promise of being able to measure stress on a very local level

Interfacial adhesion of nanoporous zeolite thin films

2006 ◽  
Vol 21 (2) ◽  
pp. 505-511 ◽  
Author(s):  
Lili Hu ◽  
Junlan Wang ◽  
Zijian Li ◽  
Shuang Li ◽  
Yushan Yan
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Interfacial Adhesion ◽  
Interfacial Strength ◽  
Future Generation ◽  
In Situ Growth ◽  
Seeded Growth ◽  
Si Substrates ◽  
Film Substrate

Nanoporous silica zeolite thin films are promising candidates for future generation low-dielectric constant (low-k) materials. During the integration with metal interconnects, residual stresses resulting from the packaging processes may cause the low-k thin films to fracture or delaminate from the substrates. To achieve high-quality low-k zeolite thin films, it is important to carefully evaluate their adhesion performance. In this paper, a previously reported laser spallation technique is modified to investigate the interfacial adhesion of zeolite thin film-Si substrate interfaces fabricated using three different methods: spin-on, seeded growth, and in situ growth. The experimental results reported here show that seeded growth generates films with the highest measured adhesion strength (801 ± 68 MPa), followed by the in situ growth (324 ± 17 MPa), then by the spin-on (111 ± 29 MPa). The influence of the deposition method on film–substrate adhesion is discussed. This is the first time that the interfacial strength of zeolite thin films-Si substrates has been quantitatively evaluated. This paper is of great significance for the future applications of low-k zeolite thin film materials.

scholarly journals Influence of Steel Grain Size on Residual Stress in Grinding Processing

2010 ◽  
Vol 638-642 ◽  
pp. 2389-2394 ◽  
Author(s):  
Masahide Gotoh ◽  
Katsuhiro Seki ◽  
M. Shozu ◽  
Hajime Hirose ◽  
Toshihiko Sasaki
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Grain Size ◽  
Stress State ◽  
Mechanical Grinding ◽  
Fine Grained ◽  
Residual Stress State ◽  
Analysis Methods ◽  
Average Grain Size ◽  
Fine Grained Steels

The fine-grained rolling steels NFG600 and the conventional usual rolling steels SM490 were processed by sand paper polishing and mechanical grinding to compare the residual stress generated after processing. The average grain size of NFG600 and SM490 is 3 μm and 15μm respectively. Therefore improvement of mechanical properties for such fine-grained steels is expected, it is important to understand the residual stress state of new fine-grained materials with processing. In this study, multi axial stresses of two kinds of specimens after polishing and grinding were measured by three kinds of analysis methods including cos-ψ method. As a result, as for σ33, the stress of NFG was compression, though that of SM490 was tension.

Nanohardness of DC Magnetron Sputtered W – C Coatings as a Function of Composition and Residual Stresses

2015 ◽  
Vol 662 ◽  
pp. 107-110 ◽  
Author(s):  
Michal Novák ◽  
František Lofaj ◽  
Petra Hviščová ◽  
Rudolf Podoba ◽  
Marián Haršáni ◽  
...  
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Magnetron Sputtering ◽  
Linear Increase ◽  
Indentation Modulus ◽  
Dc Magnetron Sputtering ◽  
Glass Substrates ◽  
Compressive Stresses ◽  
Deposition Parameters

The effects of residual stresses in thin W-C based coatings were investigated with the aim to find their influence on nanohardness and indentation modulus. Ten samples of W-C based coatings were deposited on microslide glass substrates using DC magnetron sputtering at the identical deposition parameters. Their thickness was in the range from 500 to 600 nm. The residual stresses in the coatings varied from 1.5 GPa up to 4.4 GPa. Increase of residual stress caused linear increase of HITfrom 16 to 19.5 GPa. This increase was only the result of the compressive stresses. EITof the studied coatings was not sensitive to residual stresses and corresponded to 185 GPa ± 15 GPa.

Residual Stress in Sputtered Silicon Oxycarbide Thin Films

2011 ◽  
Vol 1299 ◽  
Author(s):  
Ping Du ◽  
I-Kuan Lin ◽  
Yunfei Yan ◽  
Xin Zhang
Keyword(s):  
Thin Films ◽  
Residual Stress ◽  
Elevated Temperatures ◽  
Silicon Oxide ◽  
Composite Films ◽  
Deposition Process ◽  
Silicon Oxycarbide ◽  
X Ray ◽  
Curvature Measurement ◽  
Film Substrate

ABSTRACTSilicon carbide (SiC) has received increasing attention on the integration of microelectro-mechanical system (MEMS) due to its excellent mechanical and chemical stability at elevated temperatures. However, the deposition process of SiC thin films tends to induce relative large residual stress. In this work, the relative low stress material silicon oxide was added into SiC by RF magnetron co-sputtering to form silicon oxycarbide (SiOC) composite films. The composition of the films was characterized by Energy dispersive X-ray (EDX) analysis. The Young’s modulus and hardness of the films were measured by nanoindentation technique. The influence of oxygen/carbon ratio and rapid thermal annealing (RTA) temperature on the residual stress of the composite films was investigated by film-substrate curvature measurement using the Stoney’s equation. By choosing the appropriate composition and post processing, a film with relative low residual stress could be obtained.

Residual Stress, Fracture, and Adhesion in Sputter-Deposited Molybdenum Films

1988 ◽  
Vol 119 ◽  
Author(s):  
D. M. Mattox ◽  
R. E. Cuthrell
Keyword(s):  
Residual Stress ◽  
Strain Energy ◽  
Pressure Cycling ◽  
Stress Anisotropy ◽  
Magnetron Sputter Deposition ◽  
Magnetron Sputter ◽  
Sputter Deposited ◽  
Film Substrate ◽  
Deposited Films ◽  
Deposition Conditions

AbstractAtomistically deposited films may form with high residual stresses which may be either tensile or compressive in nature. These film stresses represent stored strain energy which may affect the adhesion of the film-substrate couple and in the limit may cause spontaneous fracture at or near the film-substrate interface (loss of adhesion). In the post cathode magnetron sputter deposition of molybdenum films, we have found that the intrinsic film stresses are generally anisotropic and may easily exceed the fracture or adhesive strength of the film-substrate couple. The residual stress anisotropy in the film is dependent on the orientation with respect to the post cathode and the magnitude and nature of the stresses are very dependent on the deposition conditions, particularly gas pressure during sputtering. By using a pressure-cycling technique, we have deposited thick (5 microns) films of molybdenum which have little residual stress or stress anisotropy.

Growth Time Optimization of Fine Grained Diamond Coated Drills for Machining CFRP

2016 ◽  
Vol 836-837 ◽  
pp. 333-339 ◽  
Author(s):  
Xin Chang Wang ◽  
Xiao Tian Shen ◽  
Tian Qi Zhao ◽  
Fang Hong Sun ◽  
Bin Shen
Keyword(s):  
Residual Stress ◽  
Protective Coatings ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Cutting Edge ◽  
Growth Time ◽  
Protective Effects ◽  
Initial Shape ◽  
Fine Grained ◽  
Film Substrate

Carbon fiber reinforced plastics (CFRP), which are widely used in the aerospace and some other new-tech industries, are considered very difficult to machine due to the material anisotropic and inhomogeneous features. Chemical vapor deposition (CVD) diamond films are suitable as protective coatings on cutting tools for machining advanced composite materials, owing to their extremely high hardness, favorable wear resistance, low friction coefficient and high thermal conductivity. Among different types of diamond films, the fine grained diamond (FGD) film can provide much more favorable environment for machining CFRP due to the small grain size, low surface roughness and the retentivity for the sharpness of the cutting edge. In the present study, aiming at drilling CFRP, FGD films of different thicknesses are deposited on Φ3 mm drills by controlling the growth time, adopting the common-used hot filament CVD (HFCVD) technology. It can be directly proved by deposition experiments that overlong growth time can induce spontaneous film delamination and removal before the cooling stage, probably as a result of the excessive residual stress concentrated on the complicated surfaces. As demonstrated by the cutting tests, with increasing the growth time, the main failure mode of the FGD coated drill changes from film delamination to flank wear/tipping to film delamination, and the maximum tool life exists when the growth time is moderate, because the flimsy film cannot provide sufficient protective effects on the film-substrate interface and even hasn’t totally cover the substrate, while there’s relatively higher residual stress in the film that is too thick, and such the residual stress can significantly deteriorate the film-substrate adhesion. Moreover, during the life cycle of each FGD film, relatively shorter growth time often means the slightly better hole quality, attributed to the retentivity of the initial shape of the uncoated drill that is optimal designed for machining CFRP, especially the weaker passivation of the cutting edge.

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