Viscoelastic Behavior of Polymer Thin‐Films Under Thermal Stresses

1996 ◽  
Vol 445 ◽  
Author(s):  
Stephen D. Bluestein ◽  
Dewi P. Y. Bramono ◽  
Ioannis N. Miaoulis ◽  
Peter Y. Wong

AbstractStresses and deformation in microelectronic packaging are affected by the viscoelastic behavior of polymer materials during manufacture or operation. Predicting and measuring these thermo‐mechanical effects is important for new devices, components, and materials. The viscoelastic response of Nycoa 851 polyimide thin‐films during thermal loading is investigated. The time‐dependent relaxation of polyimide films was measured in‐situ, focusing on the change in thermo‐mechanical properties based on the thickness of the polyimide layer. The curvature change of the multilayer structure (silver‐polyimide‐quartz heterostructure) was obtained for different temperatures and polymer film thicknesses. The polyimide relaxation time constant and activation energy were determined. Results indicate that the thermo‐mechanical properties of polyimide thin films are dependent on the thickness of the polymer layer.

1999 ◽  
Vol 565 ◽  
Author(s):  
Huey-Chiang Liou ◽  
John Pretzer

AbstractThe mechanical properties and thermal stresses of FOx thin films at different thickness and cured at different temperatures have been investigated by a nanoindentor and a profilometer. In this study, the correlation between structure change, thickness, Si-H/Si-O ratio, modulus, hardness, and calculated coefficient of thermal expansion (CTE) of FOx films have been established. The results show that the modulus of 400°C cured FOx film decreases with increasing film thickness while the hardness slightly varies with increasing film thickness. The calculated CTE of FOx film increases with increasing film thickness. In addition, both the modulus and hardness of FOx films increase with increasing curing temperature. However, the calculated CTE of FOx film decreases with increasing curing temperature. The Si-H/Si-O ratio increases with increasing film thickness but decreases with increasing curing temperature. These results indicate that the increase in modulus and hardness and the decreases in CTE for FOx films are either due to the remaining of Si-H bonds in FOx film at different film thickness or the conversion of Si-H into Si-O when forming the network structure in the FOx film at higher curing temperatures.


2003 ◽  
Vol 784 ◽  
Author(s):  
V. Rajasekarakumar ◽  
P. Victor ◽  
R. Ranjith ◽  
S. Saha ◽  
S. Rajagopalan ◽  
...  

ABSTRACTThin films of BaZrO3 (BZ) were grown using a pulsed laser deposition technique on platinum coated silicon substrates. Films showed a polycrystalline perovskite structure upon different annealing procedures of in-situ and ex-situ crystallization. The composition analyses were done using Energy dispersive X-ray analysis (EDAX) and Secondary ion mass spectrometry (SIMS). The SIMS analysis revealed that the ZrO2 formation at the right interface of substrate and the film leads the degradation of the device on the electrical properties in the case of ex-situ crystallized films. But the in-situ films exhibited no interfacial formation. The dielectric properties have been studied for the different temperatures in the frequency regime of 40 Hz to 100kHz. The response of the film to external ac stimuli was studied at different temperatures, and it showed that ac conductivity values in the limiting case are correspond to oxygen vacancy motion. The electrical modulus is fitted to a stretched exponential function and the results clearly indicate the presence of the non-Debye type of dielectric relaxation in these materials.


Coatings ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 543
Author(s):  
Yong Chen ◽  
Liangbin Hu ◽  
Changjun Qiu ◽  
Bin He ◽  
Lihua Zhou ◽  
...  

An Al2O3–TiO2 amorphous composite coating with a thickness of 100–120 μm was fabricated on China low activation martensitic steel (CLAM steel) by oxygen acetylene flame spraying technology and the laser in-situ reaction method. We investigated the microstructures and mechanical properties of the coating after liquid lead-bismuth eutectic (LBE) alloy corrosion under different temperatures for 300 h and found that the corrosion temperature of the LBE had no observable effect on the microstructure and chemical phase of the Al2O3–TiO2 amorphous composite coatings. However, the mechanical properties (micro-hardness and shear strength) of the Al2O3–TiO2 multiphase coating deteriorated slightly with the increase in the immersion temperature of the LBE. As a result of oxygen acetylene flame spraying and laser in-situ reaction technology, it was found that the Al2O3–TiO2 amorphous composite coating exhibits an excellent LBE corrosion resistance, which is a candidate structural material for the accelerator-driven subcritical system (ADS) to handle nuclear waste under extreme conditions.


2015 ◽  
Vol 7 (32) ◽  
pp. 17874-17883 ◽  
Author(s):  
Kirt A. Page ◽  
Jae Wook Shin ◽  
Scott A. Eastman ◽  
Brandon W. Rowe ◽  
Sangcheol Kim ◽  
...  

2011 ◽  
Vol 121-126 ◽  
pp. 4295-4299
Author(s):  
Hao MA Yun ◽  
Lu Ping Chao ◽  
J. S Hsu

The thesis aims to characterize the mechanical properties and stresses for thin films deposited on the circular substrates. First, the thin films with the same deposition condition were successively deposited on the distinct substrates using the evaporation technique. The phase-shifting Twyman-Green interferometer (PSTGI) was then employed to measure the warpage of the film-substrate structures and therefore the intrinsic stresses and thermal stresses can be calculated from the well-known Stoney’s formula. The coefficients of thermal expansion (CTE) and Young’s modulus of thin films were also obtained from the Stoney’s theory. Furthermore, the merit of full-field character of optical interferometry was used to propose a novel methodology using the Chen and Ou’s theory to improve the accuracy and to reduce the experiment procedures in the traditional measurement of the aforementioned mechanical properties. Finally, the measured results corresponding to the traditional and proposed methods were respectively substituted into their adopted theories to compare their difference. The results reveal that the accuracy of proposed methodology is considerably improved and the experimental procedures are reduced to those of the traditional methods.


RSC Advances ◽  
2017 ◽  
Vol 7 (36) ◽  
pp. 22094-22104 ◽  
Author(s):  
Ehsan Mohammadpour ◽  
Zhong-Tao Jiang ◽  
Mohmmednoor Altarawneh ◽  
Nicholas Mondinos ◽  
M. Mahbubur Rahman ◽  
...  

Cr1−xAlxN coatings, synthesised by an unbalanced magnetic sputtering system, showed improved microstructure and mechanical properties for ∼14–21% Al content.


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