Application of a Ag Ductile Layer in Minimizing Si Die Stresses in LDMOS Packages

2014 ◽  
Vol 605 ◽  
pp. 372-375
Author(s):  
Roselita Fragoudakis ◽  
Michael A. Zimmerman ◽  
Anil Saigal
Keyword(s):  
Layer Thickness ◽  
Thermal Stresses ◽  
Low Cost ◽  
Substrate Material ◽  
Ductile Material ◽  
Element Analysis ◽  
Cu Substrate ◽  
Die Stress ◽  
Cte Mismatch ◽  
Ductile Layer

Lateral Diffused Metal Oxide Semiconductors (LDMOS) normally have a Cu-W flange, whose CTE is matched to Si. Low cost Cu substrate material provides 2X high thermal conductivity, and along with a AuSi eutectic solder is recommended for optimal thermal performance. However, the CTE mismatch between Cu and Si can lead to failure of the semiconductor as a result of die fracture, due to thermal stresses developed during the soldering step of the manufacturing process. Introducing a Ag ductile layer is very important in minimizing such thermal stresses and preventing catastrophic failure of the semiconductor. Ag is a ductile material electroplated on the Cu substrate to absorb stresses developed during manufacturing due to the CTE mismatch between Si and Cu. The Ag layer thickness affects the magnitude of the resulting thermal stresses. This study attempts to measure the yield strength of the Ag layer, and examines the optimal layer thickness to minimize die stresses and prevent failure. The yield stress of the ductile layer deposited on a Cu flange was measured by nanoindentation. The Oliver and Pharr method was applied to obtain modulus of elasticity and yield depth of Ag. A finite element analysis of the package was performed in order to map die stress distribution for various ductile layer thicknesses. The analysis showed that increasing the ductile layer thickness up to 0.01 - 0.02 mm, decreases the Si die stresses.

scholarly journals Investigation on Die Crack in a Stacked Die Package Using Finite Element Analysis

2021 ◽  
pp. 83-91
Author(s):  
Jefferson Talledo
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Coefficient Of Thermal Expansion ◽  
Crack Problem ◽  
Element Analysis ◽  
Robust Solution ◽  
Die Attach ◽  
Die Stress ◽  
Cte Mismatch ◽  
Semiconductor Packages

Die crack is one of the problems in stacked die semiconductor packages. As silicon dies become thinner in such packages due to miniaturization requirement, the tendency to have die crack increases. This study presents the investigation done on a die crack issue in a stacked die package using finite element analysis (FEA). The die stress induced during the package assembly processes from die attach to package strip reflow was analyzed and compared with the actual die crack failure in terms of the location of maximum die stress at unit level as well as strip level. Stresses in the die due to coefficient of thermal expansion (CTE) mismatch of the package component materials and mechanical bending of the package in strip format were taken into consideration. Comparison of the die stress with actual die crack pointed to strip bending as the cause of the problem and not CTE mismatch. It was found that the die crack was not due to the thermal processes involved during package assembly. This study showed that analyzing die stress using FEA could help identify the root cause of a die crack problem during the stacked die package assembly and manufacturing as crack occurs at locations of maximum stress. The die crack mechanism can also be understood through FEA simulation and such understanding is very important in coming up with robust solution.

Compliant Stress-Engineered Interconnects for Next-Generation Packaging

2004 ◽  
Author(s):  
Kevin M. Klein ◽  
Suresh K. Sitaraman
Keyword(s):  
Life Stress ◽  
Low Cost ◽  
Intrinsic Stress ◽  
Wafer Level ◽  
Element Analysis ◽  
Operational Conditions ◽  
Technology Roadmap ◽  
Fine Pitch ◽  
Cte Mismatch ◽  
Future Demands

Future demands of microelectronic packing include increasing input/output (I/O) densities, providing high frequency capabilities, and maintaining sufficient reliability while keeping costs minimal. Organic materials with Coefficients of Thermal Expansions (CTE) over four times greater than silicon will continue to be used as future substrate materials because of their low cost. Consistent with the International Technology Roadmap for Semiconductors (ITRS, 2003), chip-to-substrate interconnects will need to have a pitch approximately equal to 40μm by the year 2012 and be able to accommodate the silicon and organic CTE mismatch without resorting to expensive reliability solutions. The demand for fine pitch chip-to-substrate interconnects combined with the CTE mismatch, creates significant demands for overall interconnect compliance as means to ensure reliability, through increasing fatigue life. Stress-engineered compliant off-chip interconnects are capable meeting future interconnect demands. Such interconnects are fabricated from stress-engineered metal thin-films using traditional IC fabrication methods and can be integrated with wafer level packing. A systematic design approach has been used to optimize interconnect geometry for use with estimated operational conditions. Finite Element Analysis (FEA) and Regression modeling have been used to create macro-models of interconnect behavior to assist in the optimization of the geometric design. Copper and Copper-Molybdenum are considered as interconnect material and the development intrinsic stress within copper is investigated via sputter deposition.

FEM Analysis of Thermal Stresses in Advanced Electronic Packages

1998 ◽  
Vol 516 ◽  
Author(s):  
Sven Rzepka ◽  
Matt A. Korhonen ◽  
Che-Yu Li ◽  
Ekkehard Meusel
Keyword(s):  
Finite Element ◽  
Flip Chip ◽  
Thermal Stresses ◽  
Low Cost ◽  
Fem Analysis ◽  
Design Guidelines ◽  
Material Behavior ◽  
General Tendency ◽  
Element Analysis ◽  
Chip Size

AbstractFollowing the general tendency of downsizing in microelectronic packages, the interposing layer between silicon chip and organic board is constantly reduced while the differences in thermal expansion stay constant. Consequently, thermal stresses have become the most important reliability concern in advanced packages. Finite element analysis is known as an effective way of theoretically studying the mechanical situation in multi-component systems with complex material behavior. The paper presents results of finite element simulations that provide practical guidance for design, process and material developments of chip size packaging (CSP), flip chip (FC), and direct chip attach (DCA) modules. Using realistic and efficient models, a low-cost CSP concept is assessed, the effects of underfill, underfill imperfections, and underfill defects on the reliability of FC modules are studied, and an optimum set of mechanical properties for underfill materials is proposed. Finally, reliability risk factors in DCA modules are identified and preliminary design guidelines are given.

Thermal Fracture of Oxidized Polydimethylsiloxane and its Implications in Soft Lithography

2011 ◽  
Author(s):  
Wes W. Tooley ◽  
Shirin Feghhi ◽  
Sangyoon J. Han ◽  
Junlan Wang ◽  
Nathan J. Sniadecki
Keyword(s):  
Soft Lithography ◽  
Thermal Stresses ◽  
Elevated Temperatures ◽  
Coefficient Of Thermal Expansion ◽  
Curing Temperature ◽  
Surface Cracks ◽  
Element Analysis ◽  
Circular Test ◽  
Cte Mismatch ◽  
Cellular Forces

During the fabrication of nanopost arrays for measuring cellular forces, we have observed surface cracks in the negative molds used to replicate the arrays from a silicon master. These cracks become more numerous and severe with each replication such that repeated castings lead to arrays with missing or broken posts. This loss in pattern fidelity from the silicon master undermines the spatial resolution of the nanopost arrays in measuring cellular forces. We hypothesized that these cracks are formed because of a mismatch in the coefficient of thermal expansion (CTE) of PDMS and its oxidized surface layer. To study the fracture of PDMS due to thermal effects, we treated circular test samples of PDMS with oxidizing plasma and then heated them to cause surface cracks. These cracks were found to be more abundant at 180 °C than at lower temperatures. Finite element analysis of a bilayer material with a CTE mismatch was used to validate that thermal stresses are sufficient to overcome the fracture toughness of oxidized PDMS when heated to a curing temperature for PDMS. As a consequence, we have ascertained that elevated temperatures are a significant detriment to the reproducibility of nanoscale features in PDMS during replica molding.

scholarly journals A Novel Electrically Small Ground-Penetrating Radar Patch Antenna with a Parasitic Ring for Respiration Detection

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 1930
Author(s):  
Di Shi ◽  
Taimur Aftab ◽  
Gunnar Gidion ◽  
Fatma Sayed ◽  
Leonhard M. Reindl
Keyword(s):  
Ground Penetrating Radar ◽  
Patch Antenna ◽  
Low Cost ◽  
Substrate Material ◽  
Geometric Parameters ◽  
Gas Explosions ◽  
Aerial Vehicle ◽  
Electromagnetic Characteristics ◽  
Ground Penetrating ◽  
Quick Search

An electrically small patch antenna with a low-cost high-permittivity ceramic substrate material for use in a ground-penetrating radar is proposed in this work. The antenna is based on a commercial ceramic 915 MHz patch antenna with a size of 25 × 25 × 4 mm3 and a weight of 12.9 g. The influences of the main geometric parameters on the antenna’s electromagnetic characteristics were comprehensively studied. Three bandwidth improvement techniques were sequentially applied to optimize the antenna: tuning the key geometric parameters, adding cuts on the edges, and adding parasitic radiators. The designed antenna operates at around 1.3 GHz and has more than 40 MHz continuous −3 dB bandwidth. In comparison to the original antenna, the −3 and −6 dB fractional bandwidth is improved by 1.8 times and 4 times, respectively. Two antennas of the proposed design together with a customized radar were installed on an unmanned aerial vehicle (UAV) for a quick search for survivors after earthquakes or gas explosions without exposing the rescue staff to the uncertain dangers of moving on the debris.

Finite Element Analysis of Creep Damage Behavior Near the Cavity on Bimaterial Interface

2006 ◽  
Vol 324-325 ◽  
pp. 951-954 ◽  
Author(s):  
Qing Min Yu ◽  
Zhu Feng Yue ◽  
Yong Shou Liu
Keyword(s):  
Finite Element ◽  
Elastic Moduli ◽  
Elastic Stress ◽  
Creep Damage ◽  
Ductile Material ◽  
Bimaterial Interface ◽  
Modulus Ratio ◽  
Element Analysis ◽  
Damage Law ◽  
The Difference

Fracture along an interface between materials plays a major role in failure of material. In this investigation, finite element calculations with Kachanov–Rabotnov damage law were carried out to study the creep damage distribution near the interface cavity in bimaterial specimens. The specimens with central hole were divided into three types. The material parameters of K-R law used in this paper were chosen for a brittle material and ductile material. All calculations were performed under four load cases. Due to the difference between elastic moduli of the bounded materials, the elastic stress field as a function of the Young’s modulus ratio (R=E1/E2) was determined. At the same time, the influence of model type on elastic stress distribution near the cavity was considered. Under the same conditions, the material with larger modulus is subjected to larger stress. The creep damage calculations show that the location of the maximum damage is different for each model. The distributions of creep damage for all three models are dependent on the material properties and load cases.

Finite Element Analysis of Thermal Stresses in Circumferential Cast Clasps of Removable Partial Dentures

2007 ◽  
Vol 23 ◽  
pp. 229-232
Author(s):  
Liliana Sandu ◽  
Nicolae Faur ◽  
Cristina Bortun ◽  
Sorin Porojan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Thermal Stresses ◽  
Element Analysis ◽  
3 Dimensional ◽  
Thermal Changes ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Back Action ◽  
Aggressive Effect

Several studies evaluated the removable partial dentures by the finite element analysis, but none of them evaluated thermal stresses. The purpose of the study was to explore the influence of thermal oral changes induced by hot/cold liquids and food on the circumferential cast clasps of removable partial dentures. A 3-dimensional finite element method was used to explore the temperature distribution, thermal stress and the influence of thermal changes on stresses and displacements of circumferential clasps during functions. Thermal variations induce stresses in dental clasps, high temperatures having a more aggressive effect than lower one. Cold liquids and food induce high stresses in the retentive clasp arms while hot ones in the occlusal rests of the clasps and for the back action clasp also in the minor connector. The study suggests the importance of consFigureidering thermal variations for stress analyses of the cast clasps.

Three Turnaround Heat Treating Studies

2003 ◽  
Author(s):  
Jaan Taagepera ◽  
Marty Clift ◽  
D. Mike DeHart ◽  
Keneth Marden
Keyword(s):  
Heat Treatment ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Thermal Stress ◽  
Thermal Stresses ◽  
Heat Treating ◽  
Element Analysis ◽  
Stress Profiles ◽  
Insight Into

Three vessel modifications requiring heat treatment were analyzed prior to and during a planned turnaround at a refinery. One was a thick nozzle that required weld build up. This nozzle had been in hydrogen service and required bake-out to reduce the potential for cracking during the weld build up. Finite element analysis was used to study the thermal stresses involved in the bake-out. Another heat treatment studied was a PWHT of a nozzle replacement. The heat treatment band and temperature were varied with location in order to minimize cost and reduction in remaining strength of the vessel. Again, FEA was used to provide insight into the thermal stress profiles during heat treatment. The fmal heat treatment study was for inserting a new nozzle in a 1-1/4Cr-1/2Mo reactor. While this material would ordinarily require PWHT, the alteration was proposed to be installed without PWHT. Though accepted by the Jurisdiction, this nozzle installation was ultimately cancelled.

Elastic Thermal Stresses in Bimetallic Pipe Welds

1980 ◽  
Vol 102 (4) ◽  
pp. 430-432 ◽  
Author(s):  
R. D. Blevins
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Intensity ◽  
Maximum Stress ◽  
Thermal Stresses ◽  
Simple Expression ◽  
Element Analysis ◽  
Maximum Stress Intensity ◽  
Bimetallic Pipe ◽  
Uniform Change

The elastic thermal stresses in a welded transition between two pipes of the same size but different alloys are explored. A stress-free temperature is postulated and the stress due to a uniform change in temperature is characterized by the maximum stress intensity in the weld. A simple expression for predicting this maximum stress intensity is developed based on the results of finite element analysis.

Performance of Low-Cost 3D Printer in Medical Application

2021 ◽  
Author(s):  
Nor Aiman Sukindar ◽  
Azib Azhari Awang Dahan ◽  
Sharifah Imihezri Syed Shaharuddin ◽  
Nor Farah Huda Abd Halim
Keyword(s):  
Low Cost ◽  
Medical Application ◽  
Fused Deposition Modelling ◽  
3D Printer ◽  
Layer By Layer ◽  
Total Deformation ◽  
Element Analysis ◽  
Porosity Level ◽  
Fused Deposition ◽  
Printing Parameters

Abstract Fused Deposition Modelling (FDM) is an additive manufacturing (AM) process that produces a physical object directly from a CAD design using layer-by-layer deposition of the filament material that is extruded via a nozzle. In industry, FDM has become one of the most used AM processes for the production of low batch quantity and functional prototypes, due to its safety, efficiency, reliability, low cost, and ability to process manufacturing-grade engineering thermoplastic. Recently, the market is flooded with the availability of low-cost printers produced by numerous companies. This research aims to investigate the effect of different porosity levels on a scaffold structure produced using a low-cost 3D printer. Comparisons of these porous structures were made in terms of Von-Mises strain, total deformation, as well as compressive stress. Various porosity levels were created by varying printing parameters, including layer height, infill density, and shell thickness by slicing the initial solid CAD file using Repetier Host 3D printing software. Finite Element Analysis (FEA) simulation was then performed on the created scaffold structures by using Ansys Workbench 19.2. The simulation result indicates that the greater porosity level will result in higher total deformation of the structure. Meanwhile, the compression test shows that the minimum strength value obtained was favourable at 22 MPa and had exceeded that of the trabecular femur (15 MPa). However, its porosity level (maximum at 52%) was still below that of the minimum threshold of porosity level of 70 percent. However, the printing parameters currently used can be adjusted in the future. Therefore, it was deduced that the low-cost 3D printer offers promising potential to fabricate different porosity structures with multiple outcomes.

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