Thermally Induced Stresses in Passivated Thin Films and Patterned Lines of AlSiCu

1994 ◽  
Vol 338 ◽  
Author(s):  
U. Burges ◽  
H. Helneder ◽  
H. KÖrner ◽  
H. Schroeder ◽  
W. Schilling
Keyword(s):  
Thin Films ◽  
Stress Relaxation ◽  
Aspect Ratio ◽  
Thermal Cycling ◽  
High Temperatures ◽  
Room Temperature ◽  
Elastic Behaviour ◽  
Thermally Induced ◽  
Induced Stresses ◽  
Beam Technique

ABSTRACTA bending beam technique was used to measure the mechanical stresses in AlSi(l%)Cu(0.5%) blanket films as well as in patterned lines (aspect ratio: 0.8) - unpassivated and passivated with SiNx - during thermal cycling from –170°C or room temperature to 450°C.Main results are:a) No significant differences in unpassivated and passivated blanket films with thickness ranging from 0.2 µm to 3.2 µm.b) In unpassivated patterned lines of 0.8 µm thickness the stresses across the lines are very small, while parallel to the lines they show nearly elastic behaviour, except at high temperatures.c) In passivated patterned lines the stresses are much higher than in blanket films, very similar parallel and across the line and nearly elastic. The stress relaxation is small compared with blanket films and depends strongly on the temperature.

Relaxation in Nanoscale Freestanding Gold Films Using MEMS

Materials ◽  
2005 ◽  
Author(s):  
B. S. Samuel ◽  
A. V. Desai ◽  
M. A. Haque
Keyword(s):  
Thin Films ◽  
Stress Relaxation ◽  
Room Temperature ◽  
Gold Films ◽  
Test Bed ◽  
Scanning Microscope ◽  
Substrate Effects ◽  
Stress Relaxation Behavior ◽  
Loading Device ◽  
Film Specimen

We present experimental results to describe the stress relaxation behavior of thin (125 nm) freestanding gold films at room temperature. The experiments were performed inside a field emission scanning microscope using a MEMS-based test bed which is only 3mm × 10mm in size. The effect of stress relaxation on the young’s modulus of gold thin films is observed. The thin film specimen used in the experiment is co-fabricated with the micromechanical loading device and hence eliminates problems of alignment and gripping. Freestanding thin films provide us with information about the mechanical behavior of thin films in the absence of substrate effects.

Thermal Cycling Fatigue In Aluminum-Alloy Thin Films On Silicon Substrate

1997 ◽  
Vol 505 ◽  
Author(s):  
J. Koike ◽  
S. Utsunomiya ◽  
K. Maruyama
Keyword(s):  
Thin Films ◽  
Residual Stress ◽  
Aluminum Alloy ◽  
Thermal Cycling ◽  
Silicon Substrate ◽  
Room Temperature ◽  
Crack Formation ◽  
Continuous Decrease ◽  
Thermal Cycling Fatigue

ABSTRACTThermal cycling was performed in Al-lmo%Si thin films deposited on Si wafers. After a given number of cycling between room temperature and 723 K, residual stress was measured at room temperure. Residual stress was found to increase with increasing the cycling number up to the 4th cycle, followed by further a continuous decrease by further cycling. The intial increase was found to be related to the increase of lattice dislcocations and their tangling. The following decrease was caused by crack formation along grain boundaties or by film delamination in some cases.

scholarly journals Stability of Tl–Ba–Ca–Cu–O superconducting thin films

1999 ◽  
Vol 14 (12) ◽  
pp. 4482-4488 ◽  
Author(s):  
M. P. Siegal ◽  
D. L. Overmyer ◽  
E. L. Venturini ◽  
R. R. Padilla ◽  
P. N. Provencio
Keyword(s):  
Thin Films ◽  
Thermal Cycling ◽  
High Temperatures ◽  
Superconducting Thin Films ◽  
Epitaxial Thin Films ◽  
Cryogenic Temperatures ◽  
The Stability

We report the stability of TlBa2CaCu2O7 and Tl2Ba2CaCu2O8 on LaAlO3(100) epitaxial thin films, under a variety of conditions. All films are stable in acetone and methanol and with repeated thermal cycling to cryogenic temperatures. Moisture, especially vapor, degrades film quality rapidly. These materials are stable to high temperatures in either N2 or O2 ambients. While total degradation, resulting from Tl depletion, occurs at the same temperatures for both phases, 600 °C in N2 and 700 °C in O2, the onset of degradation occurs at somewhat lower temperatures for TlBa2CaCu2O7 than for Tl2Ba2CaCu2O8.

Heavy Doping of Li+-ion into NiO Epitaxial Thin Films via Unequilibrium Room-temperature Processing for New Functionalization

2009 ◽  
Vol 1214 ◽  
Author(s):  
Naoki Shiraishi ◽  
Yushi Kato ◽  
Hideki Arai ◽  
Nobuo Tsuchimine ◽  
Susumu Kobayashi ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
High Temperatures ◽  
Room Temperature ◽  
Pulsed Laser ◽  
Rheed Pattern ◽  
Li Doping ◽  
Heavily Doped ◽  
Heavy Doping ◽  
Nio Films

AbstractNiO is a typical material for new p-type oxide semiconductors. Conductivity of NiO can be raised with Li+ doping. In case of Li-heavy doping, we can obtain LixNiO2(0.5< × <1.0). Recently the importance of LiNiO2 has been increased as an electrode material for rechargeable lithium cells.In this work, we tried to fabricate a novel NiO material with Li+-heavily doped by applying the pulsed laser-induced room temperature (R.T.) film process. Previously, we have succeeded in the epitaxial growth of various oxide thin films at R.T. such as Sn-doped In2O3 transparent electrodes [1]. Although the many studies have been made on the deposition of NiO epitaxial thin film at low temperatures [2], there are few reports on fabrication and the conductive characteristic for Li-heavily doped NiO epitaxial films. The film deposition at R.T., which is the unequilibrium vapor phase process, is expected to result in different crystal structure and characteristics from the films grown at high-temperatures.A composition-adjusted thin film of LixNi1-xO(0.10< × <0.40) was deposited on a sapphire (α-Al2O3)(0001) or MgO(100) substrates by pulsed laser deposition (PLD) technique in 10−6 Torr of oxygen at R.T. and the high temperatures of 350 and 515°C. Crystalline properties of thin films deposited at R.T. or high temperatures were examined using reflection high energy electron diffraction (RHEED) and X-ray diffraction. For the Li-heavily doped NiO films(x>0.30) grown at R.T., a clear streak RHEED pattern showing epitaxial growth was observed. But the Li-heavily doped NiO films grown at high temperatures, exhibited the ring RHEED pattern, which indicates the policrystal growth of films. Electric conductivity of various Li-doped NiO thin films deposited at R.T. or high temperatures on sapphire (0001) substrates were measured by two-probe method. The interesting results were obtained that conductivity of the film was increased remarkably with an increase of Li-doping for R.T. deposition, but was not changed so much regardless of Li-doping for high-temperature depositions.

Growth of Au on A Ge (111) Surface

1991 ◽  
Vol 237 ◽  
Author(s):  
D. N. Dunn ◽  
P. Xu ◽  
L. D. Marks
Keyword(s):  
Thin Films ◽  
Single Crystal ◽  
High Temperatures ◽  
Room Temperature ◽  
Annealing Behavior ◽  
Temperature Growth ◽  
Au Thin Films

ABSTRACTWe investigate the room temperature growth of evaporated Au thin films on both clean and dirty single crystal Ge (111) substrates. The annealing behavior of these films was then examined under low and high temperatures.

The Effect of Ultra-Low Temperature Treatments on the Stress in Aluminum Metallization on Silicon Wafers

1994 ◽  
Vol 338 ◽  
Author(s):  
Frank Baldwin ◽  
Paul H. Holloway ◽  
Mark Bordelon ◽  
Thomas R. Watkins
Keyword(s):  
Stress Relaxation ◽  
Low Temperature ◽  
Thermal Cycling ◽  
Liquid Nitrogen ◽  
Room Temperature ◽  
Silicon Wafers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Aluminum Metallization ◽  
Low Temperature Treatments

ABSTRACTThe stresses in Al-0.75w%Si-0.5w%Cu unpatterned metallization on silicon wafers have been measured using substrate curvature and x-ray diffraction techniques after quenching in liquid nitrogen. Stresses were measured with and without phospho-silicate glass overlayers and SiO2 underlayers, and thermal cycling followed by relaxation at room temperature. It was found that cooling the substrates to 77 K and warming to room temperature caused the metallization stress to go from tensile to compressive. Subsequent heating of the substrates to above ∼70°C followed by cooling to room temperature caused the stress to become tensile. Both compressive and tensile stresses were found to relax at room temperature with a time constant of 2.3 ± 0.2 hours. The magnitude of stress relaxation was a function of temperature, being about 20 MPa after heating to 240°C. The metallization exhibited both compressive and tensile flow stresses of ∼100 MPa near room temperature.

Stresses in Multilayered Thin Films on a Thick Substrate

1987 ◽  
Vol 91 ◽  
Author(s):  
E. Suhir
Keyword(s):  
Thin Films ◽  
Fatigue Strength ◽  
Structural Characteristics ◽  
Normal Stresses ◽  
Thermally Induced ◽  
Heteroepitaxial Structures ◽  
Thick Substrate ◽  
Induced Stresses ◽  
Multilayered Thin Films ◽  
Distribution Of Stresses

ABSTRACTThe analysis contains an engineering method for the prediction of thermally induced stresses in single- and multilayered heteroepitaxial structures on a thick substrate. The examined stresses include 1) normal stresses acting in the film layers themselves and responsible for their ultimate and fatigue strength, and 2) interfacial stresses responsible for film blistering and peeling. The developed formulas are simple, visible, easy-to-use, and clearly indicate how material and structural characteristics affect the magnitude and the distribution of stresses and deflections. Some recommendations for smaller stresses in film structures are presented. The obtained results can be utilized as a guidance for an optimal physical design of multilayered heteroepitaxial structures used in Microelectronics.

Isothermal Stress Relaxation in Passivated Alsicu- and Al- Lines with Different Aspect Ratios

1997 ◽  
Vol 473 ◽  
Author(s):  
Ch. Roths ◽  
J. Hönings ◽  
I. Eppler ◽  
H. Schroeder
Keyword(s):  
Stress Relaxation ◽  
Aspect Ratio ◽  
Thermal Cycling ◽  
Hydrostatic Stress ◽  
Aspect Ratios ◽  
Amplitude Increase ◽  
Different Temperatures ◽  
Shear Relaxation ◽  
Underlying Mechanisms ◽  
Stress Hysteresis

ABSTRACTMechanical stress relaxation in passivateci metal lines generally has two components, shear relaxation at constant volume, changing the stress distribution, and volumetric relaxation changing the hydrostatic stress. In order to contribute to the understanding of the underlying mechanisms we have collected detailed data on relaxation of passivated Al- and AlSiCu-lines with different aspect ratios a (0.2 ≤ a ≤ 1) and different thicknesses. A bending beam technique was used to measure the stress of these lines during thermal cycling from RT to 450°C and isothermal relaxation at different temperatures between RT and 350°C. Main results are: i) During thermal cycling the stress at RT and the total stress amplitude increase with increasing aspect ratio a, while stress hysteresis formation increases with decreasing a. ii) During isothermal relaxation the relaxed stress is strongly dependent on temperature with maxima between 150 and 250°C. The maximum shifts to lower temperatures with decreasing aspect ratio. From the temperature dependence the effective activation energy of 0.6±0.3eV for AlSiCu can be determined, iii) Finite element calculation and the method of “eigenstrains” are used to estimate seperately volumetric (voiding) and shear plasticity in these lines. Clearly voiding dominates the isothermal stress relaxation in all measured samples.

An Approximate Analysis of Stresses in Multilayered Elastic Thin Films

1988 ◽  
Vol 55 (1) ◽  
pp. 143-148 ◽  
Author(s):  
E. Suhir
Keyword(s):  
Thin Films ◽  
Structural Characteristics ◽  
Finite Size ◽  
Approximate Analysis ◽  
Normal Stresses ◽  
Approximate Evaluation ◽  
Thermally Induced ◽  
Heteroepitaxial Structures ◽  
Induced Stresses ◽  
Distribution Of Stresses

The analysis contains an engineering method for the approximate evaluation of thermally induced stresses in single and multilayered heteroepitaxial structures fabricated on thick substrates, with consideration of the finite size of the structure. The examined stresses include normal stresses, acting in the film layers themselves and responsible for their ultimate and fatigue strength, as well as interfacial stresses, responsible for film blistering and peeling. The developed formulas are simple, easy-to-use, and clearly indicate how material and structural characteristics affect the magnitude and the distribution of stresses and deflections. Some recommendations for smaller stresses in film structures are presented. The obtained results can be utilized as a guidance for physical design of multilayered heteroepitaxial structures in microelectronics.

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