Influence of internal mechanical stress and strain on electrical performance of polyethylene electrical treeing resistance

1996 ◽  
Vol 3 (2) ◽  
pp. 248-257 ◽  
Author(s):  
E. David ◽  
J.-L. Parpal ◽  
J.-P. Crine
Keyword(s):  
Mechanical Stress ◽  
Electrical Performance ◽  
Stress And Strain ◽  
Internal Mechanical Stress ◽  
Electrical Treeing

Electrical-Thermal-Reliability Co-Design for TSV-Based 3D-ICs

2015 ◽  
Author(s):  
Tiantao Lu ◽  
Ankur Srivastava
Keyword(s):  
Mechanical Stress ◽  
Electrical Performance ◽  
Mechanical Reliability ◽  
Thermal Reliability ◽  
Conduction Path ◽  
Placement Problem ◽  
Thermal Profile ◽  
3D Ic ◽  
3D Ics ◽  
Simulation Based

This paper presents an electrical-thermal-reliability co-design technique for TSV-based 3D-ICs. Although TSV-based 3D-IC shows significant electrical performance improvement compared to traditional 2D circuit, researchers have reported strong electromigration (EM) in TSVs, which is induced by the thermal mechanical stress and the local temperature hotspot. We argue that rather than addressing 3D-IC’s EM issue after the IC designing phase, the designer should be aware of the circuit’s thermal and EM properties during the IC designing phase. For example, one should be aware that the TSVs establish vertical heat conduction path thus changing the chip’s thermal profile and also produce significant thermal mechanical stress to the nearby TSVs, which deteriorates other TSV’s EM reliability. Therefore, the number and location of TSVs play a crucial role in deciding 3D-IC’s electrical performance, changing its thermal profile, and affecting its EM-reliability. We investigate the TSV placement problem, in order to improve 3D-IC’s electrical performance and enhance its thermal-mechanical reliability. We derive and validate simple but accurate thermal and EM models for 3D-IC, which replace the current employed time-consuming finite-element-method (FEM) based simulation. Based on these models, we propose a systematic optimization flow to solve this TSV placement problem. Results show that compared to conventional performance-centered technique, our design methodology achieves 3.24x longer EM-lifetime, with only 1% performance degradation.

scholarly journals Stresses and strains on the human fetal skeleton during development

2018 ◽  
Vol 15 (138) ◽  
pp. 20170593 ◽  
Author(s):  
Stefaan W. Verbruggen ◽  
Bernhard Kainz ◽  
Susan C. Shelmerdine ◽  
Joseph V. Hajnal ◽  
Mary A. Rutherford ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Three Dimensional ◽  
Late Pregnancy ◽  
In Utero ◽  
Future Research ◽  
Stress And Strain ◽  
Human Skeleton ◽  
Skeletal Malformations ◽  
Fetal Movements ◽  
Potential Link

Mechanical forces generated by fetal kicks and movements result in stimulation of the fetal skeleton in the form of stress and strain. This stimulation is known to be critical for prenatal musculoskeletal development; indeed, abnormal or absent movements have been implicated in multiple congenital disorders. However, the mechanical stress and strain experienced by the developing human skeleton in utero have never before been characterized. Here, we quantify the biomechanics of fetal movements during the second half of gestation by modelling fetal movements captured using novel cine-magnetic resonance imaging technology. By tracking these movements, quantifying fetal kick and muscle forces, and applying them to three-dimensional geometries of the fetal skeleton, we test the hypothesis that stress and strain change over ontogeny. We find that fetal kick force increases significantly from 20 to 30 weeks' gestation, before decreasing towards term. However, stress and strain in the fetal skeleton rises significantly over the latter half of gestation. This increasing trend with gestational age is important because changes in fetal movement patterns in late pregnancy have been linked to poor fetal outcomes and musculoskeletal malformations. This research represents the first quantification of kick force and mechanical stress and strain due to fetal movements in the human skeleton in utero , thus advancing our understanding of the biomechanical environment of the uterus. Further, by revealing a potential link between fetal biomechanics and skeletal malformations, our work will stimulate future research in tissue engineering and mechanobiology.

Stretchable Dielectric Material for Conformable Bioelectronic Devices

2006 ◽  
Vol 926 ◽  
Author(s):  
Candice Tsay ◽  
Stephanie P. Lacour ◽  
Sigurd Wagner ◽  
Zhe Yu ◽  
Barclay Morrison
Keyword(s):  
Mechanical Stress ◽  
Tensile Strain ◽  
Dielectric Material ◽  
Electronic Devices ◽  
Hippocampal Slices ◽  
Dielectric Strength ◽  
Electrical Performance ◽  
Living Tissue ◽  
Silicone Polymer

ABSTRACTWe use a photo-patternable silicone polymer to fabricate an elastically deformable encapsulation film on stretchable gold lines that electrically conduct while stretched to >50% strain. To detect bioelectrical signals, these stretchable gold lines are patterned as leads and micro-electrodes. They need to be encapsulated with a material that is electrically insulating, as stretchable as the elastomeric substrate, and that can be readily patterned to define recording sites. First, we evaluate the biocompatibility of the elastic encapsulation polymer by assessing the viability of the organotypic hippocampal slices cultured on it. Then, to test the electrical performance of the encapsulation film under large mechanical stress, we measure the dielectric strength of the encapsulation film to 50% tensile strain. Our findings indicate that the photo-patternable silicone material is a suitable interface toin vitroliving tissue, and is a reliable stretchable insulator for soft and conformable electronic devices.

Study of Warpage and Mechanical Stress of 2.5D Package Interposers during Chip and Interposer Mount Process

2012 ◽  
Vol 2012 (1) ◽  
pp. 000967-000974 ◽  
Author(s):  
Takashi Hisada ◽  
Yasuharu Yamada ◽  
Junko Asai ◽  
Toyohiro Aoki
Keyword(s):  
Mechanical Stress ◽  
Dielectric Layer ◽  
Coefficient Of Thermal Expansion ◽  
Transmission Rate ◽  
Organic Substrate ◽  
Electrical Performance ◽  
Von Mises Stress ◽  
Design Elements ◽  
Plastic Ball ◽  
Low K

As data transmission rate increases, flip chip plastic ball grid array (FCPBGA) utilizing a interposer for multiple chips is gaining popularity because of high electrical performance, ease of chip design, ease of thermal management with thermal lid, etc. The authors assessed package design configuration and key design elements for two chips application assuming 1600 signal I/Os for logic and 800 signal I/Os for memory. Then, we studied warpage behavior of the interposer, and mechanical stress of solder interconnections and low-k dielectric layer under controlled collapse chip connection (C4) pad. We set three different mount process assumptions for chip to interposer and interposer to base organic substrate. The mount process assumptions are (1) two pass reflow of chip to interposer first, then interposer to base organic substrate, (2) reversed sequence of two pass reflow which is interposer to base organic substrate first, then chip to interposer, (3) one pass reflow of chip, interposer and base organic substrate all together. We also set three different interposer material assumptions of Si, glass and organic in this study. We analyzed warpage behavior and mechanical stress using finite element method (FEM) modeling technique with a set of combinations of coefficient of thermal expansion (CTE) and elastic modulus of the interposers. The study also includes an analysis for conventional multi-chip-module (MCM) FCPBGA as a reference. We show the analysis results of interposer warpage, first principal stress at low-k dielectric layer under C4 pad and von Mises stress at solder interconnections of chip joining and interposer joining.

Mechanical stress of the electrical performance of polycrystalline-silicon resistors

2001 ◽  
Vol 16 (9) ◽  
pp. 2579-2582 ◽  
Author(s):  
N. Nakabayashi ◽  
H. Ohyama ◽  
E. Simoen ◽  
M. Ikegami ◽  
C. Claeys ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Polycrystalline Silicon ◽  
Chemical Vapor ◽  
Silicon Wafers ◽  
External Stress ◽  
Electrical Performance ◽  
Structural Differences ◽  
Pressure Chemical ◽  
Si Films ◽  
The Impact

Results are presented of a study on the mechanical stress dependence of the resistance of polycrystalline silicon (Poly-Si) films doped with different atomic species. Two types of Poly-Si film implanted with boron and phosphorus ions were studied, namely, B-doped films of 400 nm and P-doped films of 250 nm thickness, which were deposited by low-pressure chemical vapor deposition at 620 °C on thermally oxidized silicon wafers. The film doping was done by ion implantation at 50 keV, with a dose of boron and phosphorus of 2 × 1014 and 5.3 × 1014 cm−2, respectively. The Poly-Si films were annealed in a N2 ambient at 1000 °C for 20 min to activate the implanted atoms. A controlled amount of external stress was applied to the silicon wafers to study the impact on the electrical performance of the implanted Poly-Si resistors. The resistance of the B-doped Poly-Si films is shown to increase by the mechanical stress, while the resistance of the P-implanted Poly-Si films remained unchanged. It is concluded that this difference is related to the structural differences between Poly-Si films implanted with boron and phosphorus, respectively.

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