Experiments with in-situ thin film telephone cord buckling delamination propagation

MRS Proceedings ◽

10.1557/proc-749-w10.7 ◽

2002 ◽

Vol 749 ◽

Cited By ~ 13

Author(s):

Alex A. Volinsky

Keyword(s):

Thin Film ◽

Residual Stress ◽

Compressive Residual Stress ◽

In Situ Observation ◽

Crack Healing ◽

Buckling Delamination ◽

Film Substrate ◽

Delamination Propagation ◽

Analysis Of Motion

ABSTRACTThere are many different stress relief mechanisms observed in thin films. One of the mechanisms involves film debonding from the substrate. In the case of tensile residual stress a network of through-thickness cracks forms in the film. In the case of compressive residual stress thin film buckling and debonding from the substrate in the form of blisters is observed. The buckling delamination blisters can be either straight, or form periodic buckling patterns commonly known as telephone cord delamination morphology.The mechanics of straight-sided blisters is well understood. Current study relies on the in-situ observation of phone cord delamination propagation in different thin film/substrate systems. Both straight and phone cord delaminations are shown to simultaneously propagate in the same film system. Straight-sided blisters propagate several times faster than the phone cords, and may be followed by thin film fracture along the line of maximum film buckling amplitude. Phone cord delaminations originally start as straight-sided blisters, but then deviate to the periodic phone cord geometry due to the fact that the compressive residual stress in the film is biaxial. Digital analysis of motion recordings shows that partial crack “healing” is present at the curved portions of the phone cords due to the “secondary” buckling pushing thin film back to the substrate. These experimental observations allow for the correct interpretation of the telephone cord delamination morphology.

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Interfacial adhesion of nanoporous zeolite thin films

Journal of Materials Research ◽

10.1557/jmr.2006.0060 ◽

2006 ◽

Vol 21 (2) ◽

pp. 505-511 ◽

Cited By ~ 10

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.

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The Effect of Stress on the Nanomechanical Properties of Au Surfaces

MRS Proceedings ◽

10.1557/proc-440-177 ◽

1996 ◽

Vol 440 ◽

Cited By ~ 1

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

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Residual Stresses for In-Situ Deposition of Thin-Film High-Temperature Superconductors

Journal of Electronic Packaging ◽

10.1115/1.2905695 ◽

1994 ◽

Vol 116 (4) ◽

pp. 249-257 ◽

Cited By ~ 9

Author(s):

P. E. Phelan ◽

M. N. Ghasemi Nejhad

Keyword(s):

Thin Film ◽

Residual Stress ◽

Residual Stresses ◽

High Temperature Superconductors ◽

Oxygen Stoichiometry ◽

Chemical Shrinkage ◽

In Situ Deposition ◽

Cell Dimensions ◽

Unit Cell Dimensions

Residual stresses are caused by nonuniform thermal expansion and chemical shrinkage taking place during processing. For thin-film high-temperature superconductors, residual stresses result because of the thermal expansion mismatch between the film and substrate, and the introduction of oxygen into the film after in-situ deposition, which makes the unit cell dimensions change (chemical shrinkage) as the oxygen stoichiometry changes. Since both the reliability of the film—especially the bond between the film and substrate—and the film critical temperature are functions of the state of stress, it is important to understand how the residual stresses vary with processing conditions. Here, a three-dimensional residual stress analysis is carried out based on laminate theory, which assumes the lateral dimensions of the entire system to be much larger than its thickness. The normal residual stress components in the film, and the peeling stress at the film/substrate interface, are calculated. The results demonstrate the crucial role that chemical shrinkage plays in the formulation of residual stresses. A large portion of the stresses arises from the initial change of the unit cell dimensions due to changes in the film oxygen stoichiometry. Therefore, the processing temperature, and especially the initial oxygen pressure in the deposition chamber, are the key variables that impact the residual stresses.

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ANNEALING OF POLYCRYSTALLINE THIN FILM SILICON SOLAR CELLS IN WATER VAPOUR AT SUB-ATMOSPHERIC PRESSURES

Acta Polytechnica ◽

10.14311/ap.2014.54.0341 ◽

2014 ◽

Vol 54 (5) ◽

pp. 341-347

Author(s):

Peter Pikna ◽

Vlastimil Píč ◽

Vítězslav Benda ◽

Antonín Fejfar

Keyword(s):

Thin Film ◽

Solar Cells ◽

Solar Cell ◽

Water Vapour ◽

Elevated Temperatures ◽

Voltage Response ◽

In Situ Observation ◽

Polycrystalline Thin Film ◽

Cell Parameters

Thin film polycrystalline silicon (poly-Si) solar cells were annealed in water vapour at pressures below atmospheric pressure. PN junction of the sample was contacted by measuring probes directly in the pressure chamber filled with steam during passivation. Suns-VOC method and a Lock-in detector were used to monitor an effect of water vapour to VOC of the solar cell during whole passivation process (in-situ). Tested temperature of the sample (55°C – 110°C) was constant during the procedure. Open-circuit voltage of a solar cell at these temperatures is lower than at room temperature. Nevertheless, voltage response of the solar cell to the light flash used during Suns-VOC measurements was good observable. Temperature dependences for multicrystalline wafer-based and polycrystalline thin film solar cells were measured and compared. While no significant improvement of thin film poly-Si solar cell parameters by annealing in water vapour at under-atmospheric pressures was observed up to now, in-situ observation proved required sensitivity to changing VOC at elevated temperatures during the process.

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