scholarly journals ZRO Drift Reduction of MEMS Gyroscopes via Internal and Packaging Stress Release

Micromachines ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1329
Author(s):  
Pengfei Xu ◽  
Zhenyu Wei ◽  
Lu Jia ◽  
Yongmei Zhao ◽  
Guowei Han ◽  
...  
Keyword(s):  
Thermal Stresses ◽  
Stress Release ◽  
Release Process ◽  
Practical Applications ◽  
Induced Stress ◽  
Mems Gyroscopes ◽  
Zero Rate ◽  
Packaging Structure ◽  
Stress Release Process ◽  
Release Method

Zero-rate output (ZRO) drift induces deteriorated micro-electromechanical system (MEMS) gyroscope performances, severely limiting its practical applications. Hence, it is vital to explore an effective method toward ZRO drift reduction. In this work, we conduct an elaborate investigation on the impacts of the internal and packaging stresses on the ZRO drift at the thermal start-up stage and propose a temperature-induced stress release method to reduce the duration and magnitude of ZRO drift. Self-developed high-Q dual-mass tuning fork gyroscopes (TFGs) are adopted to study the correlations between temperature, frequency, and ZRO drift. Furthermore, a rigorous finite element simulation model is built based on the actual device and packaging structure, revealing the temperature and stresses distribution inside TFGs. Meanwhile, the relationship between temperature and stresses are deeply explored. Moreover, we introduce a temperature-induced stress release process to generate thermal stresses and reduce the temperature-related device sensitivity. By this way, the ZRO drift duration is drastically reduced from ~2000 s to ~890 s, and the drift magnitude decreases from ~0.4 °/s to ~0.23 °/s. The optimized device achieves a small bias instability (BI) of 7.903 °/h and a low angle random walk (ARW) of 0.792 °/√ h, and its long-term bias performance is significantly improved.

scholarly journals ZRO Drift Reduction of MEMS Gyroscopes via Internal and Packaging Stress Release

2021 ◽  
Author(s):  
Pengfei Xu ◽  
Zhenyu Wei ◽  
Lu Jia ◽  
Yongmei Zhao ◽  
Guowei Han ◽  
...  
Keyword(s):  
Thermal Stresses ◽  
Stress Release ◽  
Release Process ◽  
Practical Applications ◽  
Induced Stress ◽  
Mems Gyroscopes ◽  
Zero Rate ◽  
Packaging Structure ◽  
Stress Release Process ◽  
Release Method

Zero-rate output (ZRO) drift induces deteriorated micro-electromechanical system (MEMS) gy-roscope performances, severely limiting its practical applications. Hence, it is vital to explore an effective method toward ZRO drift reduction. In this work, we conduct an elaborate investigation on the impacts of the internal and packaging stresses on the ZRO drift at the thermal start-up stage, and propose a temperature-induced stress release method to reduce the duration and magnitude of ZRO drift. Self-developed high-Q dual mass tuning fork gyroscopes (TFGs) are adopted to study the correlations between temperature, frequency and ZRO drift. Furthermore, a rigorous finite element simulation model is built based on the actual device and packaging structure, revealing the temperature and stresses distribution inside TFGs. Meanwhile, the relationship between temperature and stresses are deeply explored. Moreover, we introduce a temperature-induced stress release process to generate thermal stresses and reduce the temperature-related device sensitivity. By this way, the ZRO drift duration is drastically reduced from ~2000 s to ~890 s, and the drift magnitude decreases from ~0.4 °/s to ~0.23 °/s. This stress release method achieves a small bias instability (BI) of 7.903 °/h and a low angle random walk (ARW) of 0.792 °/√h, and the long-term bias performance is significantly improved.

scholarly journals Autocorrelations in pulsar glitch waiting times and sizes

2019 ◽  
Vol 488 (4) ◽  
pp. 4890-4896 ◽  
Author(s):  
J B Carlin ◽  
A Melatos
Keyword(s):  
Waiting Time ◽  
Waiting Times ◽  
P Value ◽  
Spearman Correlation ◽  
Stress Release ◽  
Release Process ◽  
Meta Model ◽  
State Dependent ◽  
Cross Correlations ◽  
Stress Release Process

ABSTRACT Among the five pulsars with the most recorded rotational glitches, only PSR J0534+2200 is found to have an autocorrelation between consecutive glitch sizes that differs significantly from zero (Spearman correlation coefficient ρ = −0.46, p-value = 0.046). No statistically compelling autocorrelations between consecutive waiting times are found. The autocorrelation observations are interpreted within the framework of a predictive meta-model describing stress release in terms of a state-dependent Poisson process. Specific combinations of size and waiting time autocorrelations are identified, alongside combinations of cross-correlations and size and waiting time distributions, that are allowed or excluded within the meta-model. For example, future observations of any ‘quasi-periodic’ glitching pulsar, such as PSR J0537–6910, should not reveal a positive waiting time autocorrelation. The implications for microphysical models of the stress-release process driving pulsar glitches are discussed briefly.

Stress release process along a crustal fault analogous to the plate boundary: a case study of the 2017 M5.2 Akita-Daisen earthquake, NE Japan

2020 ◽  
Author(s):  
Keisuke Yoshida ◽  
Taka'aki Taira ◽  
Yoshiaki Matsumoto ◽  
Tatsuhiko Saito ◽  
Kentaro Emoto ◽  
...  
Keyword(s):  
Plate Boundary ◽  
Stress Release ◽  
Release Process ◽  
Stress Release Process ◽  
Ne Japan

Stress release process along an intraplate fault analogous to the plate boundary: a case study of the 2017 M5.2 Akita-Daisen earthquake, NE Japan

2020 ◽  
Author(s):  
Keisuke Yoshida ◽  
Taka'aki Taira ◽  
Yoshiaki Matsumoto ◽  
Tatsuhiko Saito ◽  
Kentaro Emoto ◽  
...  
Keyword(s):  
Plate Boundary ◽  
Stress Release ◽  
Release Process ◽  
Stress Release Process ◽  
Ne Japan

Effect of Compliance on Residual Stresses in Manufacturing with Moving Heat Sources

2021 ◽  
pp. 1-53
Author(s):  
Mitchell R. Grams ◽  
Patricio F. Mendez
Keyword(s):  
Residual Stresses ◽  
Thermal Stresses ◽  
Ad Hoc ◽  
Mathematical Treatment ◽  
Heat Sources ◽  
Plastic Part ◽  
Practical Applications ◽  
Tendon Force ◽  
Design Calculations ◽  
Force Concept

Abstract Manufacturing processes involving moving heat sources include additive manufacturing, welding, laser processing (cladding and heat treatment), machining, and grinding. These processes involve high local thermal stresses that induce plasticity and result in permanent residual stress and distortion. The residual stresses are typically calculated numerically at great computational expense despite the fact that the inelastic fraction of the domain is very small. Efforts to decouple the small plastic part from the large elastic part have led to the development of the tendon force concept. The tendon force can be predicted analytically for the case of infinitely rigid components; however, this limitation has prevented the broader use of the concept in practical applications. This work presents a rigorous mathematical treatment using dimensional analysis, asymptotics, and blending which demonstrates that the effect of geometric compliance depends on a single dimensionless group, the Okerblom number. Closed-form expressions are derived to predict the effect of compliance without the need for empirical ad-hoc fitting or calibration. The proposed expressions require input of only material properties and tabulated process parameters, and are thus ideally suited for use in metamodels and design calculations, as well as incorporation into engineering codes and standards.

DEVELOPMENT OF AN ULTRA THIN DIE-TO-WAFER FLIP CHIP STACKING PROCESS FOR 2.5D INTEGRATION

2013 ◽  
Vol 2013 (1) ◽  
pp. 000516-000522 ◽  
Author(s):  
G. Parès ◽  
A. Attard ◽  
F. Dosseul ◽  
A. N'Hari ◽  
O. Boillon ◽  
...  
Keyword(s):  
Flip Chip ◽  
Transient Liquid Phase ◽  
High Yield ◽  
Integration Scheme ◽  
Wafer Level ◽  
Release Process ◽  
Process Improvements ◽  
Low Profile ◽  
Stress Release Process ◽  
Tin Silver Copper

3D integration relying on novel vertical interconnection technologies opens the gate to powerful microelectronic systems in ultra-thin packages answering the demand of the mobile market. Among these, die-to-wafer stacking is a key enabling technology for 2.5D as well as for 3D with technological challenges driven by, in one hand, the increase of the die surface and the number of I/Os and, on the other hand, the reduction of the vertical dimensions. In our integration scheme we have achieved flip chip stacking (or Face to Face) of 35 μm ultra-thin dies with low stand-off (< 15 μm) copper micro-bumps and tin-silver-copper solders (SAC). Ultra-thin dies are prepared using dicing before grinding (DBG) technique. After DBG, plasma stress release process is applied to the backside of the singulated chips. Copper μbump technology is challenging with this very low profile stacking since the current flip chip process is no longer adapted to this geometry and that the die flatness tolerance become very critical to obtain a high soldering yield. Process improvements have been achieved on the copper pillar fabrication itself with several metallurgy stack configurations as well as new processes using damascene techniques. Furthermore, innovative technologies have been deployed on the pick and place and collective soldering processes. Intermetallic formation during reflow process is achieved through transient liquid phase (TLP) reaction leading to thorough consumption of the tin layer and to the formation of Cu6Sn5 and Cu3Sn compounds. Capillary underfill is finally successfully applied in the narrow die-to-wafer gap by jetting technique. After optimization, electrical tests show a very high yield close to 100% over a representative number of fully populated wafers. Reliability tests have also been carried out at wafer level exhibiting no significant resistance increase or yield loss over 1000 thermal cycles between −40 and +125°C.

Formation of transition-metal-based ohmic contacts to n-Mg2Si by Plasma Activated Sintering

2007 ◽  
Vol 1044 ◽  
Author(s):  
Yohei Oguni ◽  
Tsutomu Iida ◽  
Atsunobu Matsumoto ◽  
Takashi Nemoto ◽  
Junichi Onosaka ◽  
...  
Keyword(s):  
Ohmic Contacts ◽  
Thermal Stresses ◽  
Electrode Materials ◽  
Open Circuit ◽  
Activated Sintering ◽  
Practical Applications ◽  
Thermal Expansion Coefficients ◽  
Good Crystalline Quality ◽  
The Difference ◽  
Plasma Activated Sintering

AbstractElectrode materials consisting of Cu, Ti and Ni were formed on Bi-doped n-type Mg2Si by means of a monobloc plasma-activated sintering (PAS) technique. Due to the difference in thermal expansion coefficients between Ti and Mg2Si, rather high residual thermal stresses gave rise to the introduction of cracks, which were mainly located in the Mg2Si layer, when Ti was used as the electrode material. In the case of the Cu electrodes, monobloc sintering could not be performed in a reproducible manner because Cu melts abruptly and effuses at around 973K, which is 100 K lower than the sintering temperature that is required for Mg2Si of good crystalline quality. When compared with the results for Cu and Ti, the monobloc PAS process for Ni was both stable and reproducible. The room-temperature I-V characteristics of Ni electrodes were considered to be adequate for practical applications, with durable Mg2Si-electrode junction properties being realized at a practical operating temperature of 600 K with ΔT = 500 K. The highest open circuit voltage (VOC) observed was 41 mV at ΔT = 500 K (between 873 K and 373 K) for Ni electrodes fabricated using the monobloc PAS process. The voltage (V) and current (I) values with a 10 Ohm load were ∼ 48 mV and ∼ 2 mA at ΔT = 500 K.

Comparison of Thermal and Stress Analysis Results for a High Voltage Module Using FEA and a Quick Parametric Analysis Tool

2018 ◽  
Author(s):  
L. M. Boteler ◽  
S. M. Miner
Keyword(s):  
Stress Analysis ◽  
High Voltage ◽  
Parametric Analysis ◽  
Thermal Stresses ◽  
Analysis Tool ◽  
Element Analysis ◽  
Module Design ◽  
Fast Running ◽  
Packaging Structure ◽  
Low Order

A low order fast running parametric analysis tool, ParaPower, was used to arrive at the design for a novel high voltage module. The low order model used a 3D nodal network to calculate device temperatures and thermal stresses. The model assumed heat flux generated near the top surface of each device which is then conducted through the packaging structure and removed by convection. The temperature distribution is used to calculate thermal stresses throughout the package. This co-design modeling tool, developed for rectilinear geometries, allowed a rapid evaluation of the package temperatures and CTE induced stresses throughout the design space. However, once the final design configuration was determined a detailed finite element analysis was performed to validate the design. This paper compares the results obtained using ParaPower to the FEA, demonstrating the usefulness of the parametric analysis tool. Results for both temperature and CTE induced stress are compared. Two different stress models are evaluated. One based on the more traditional planar module design, which assumes a substantial substrate or heat spreader on which the module is assembled. The other model is less restrictive, eliminating the requirement for a substrate. The FEA modeling was performed using SolidWorks beginning with a thermal analysis followed by a stress analysis based on the temperature solution. Both the values and the trends of the temperatures and stresses were evaluated. The temperature results agreed to within 3.2°C. The trends and sign of the stresses were correctly predicted, but the magnitudes were not. One of the significant advantages of ParaPower is the speed of the computation. The run time for the parametric analysis was roughly two orders of magnitude faster than the FEA. This made it possible to build the model and complete the parametric analysis of roughly 500 runs in less than a day.

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