An analytical thermal and stress analysis tool for die attach optimization in GaN power amplifier (PA) applications

2012 ◽  
Author(s):  
Quan Qi ◽  
D. Monthei
Keyword(s):  
Stress Analysis ◽  
Power Amplifier ◽  
Analysis Tool ◽  
Die Attach

Development of Lifting and Lowering-in Plan for the Control of Construction Stresses

2020 ◽  
Author(s):  
Jiawei Wang ◽  
Yong-Yi Wang ◽  
William A. Bruce ◽  
Steve Rapp ◽  
Russell Scoles
Keyword(s):  
Stress Analysis ◽  
Analysis Tool ◽  
Graphical Interface ◽  
Height Range ◽  
The Core ◽  
Extensive Analysis ◽  
Concrete Coating ◽  
Cross Country ◽  
Girth Welds ◽  
Core Functionality

Abstract Construction of a cross-country pipeline involves lifting the pipeline off the skids and lowering it into the trench (lifting and lowering-in). This can introduce the highest stress magnitude that the pipe may experience over its service life. If not managed properly, overly high stresses may cause integrity issues during construction and/or service. If the girth welds are qualified and accepted using alternative flaw acceptance criteria, such as those in API 1104 Annex A and CSA Z662 Annex K, these stresses must be kept below a preset level during lifting and lowering-in to satisfy the requirements of those standards. This paper covers the development and usage of a stress analysis tool for the continuous lifting and lowering-in of pipe strings without a concrete coating or river weights. The outcome of the stress analysis can be used to develop lifting and lowering-in plans for construction crews. The core functionality of the application tool is to calculate the stresses from bending in the vertical and horizontal planes. The stresses from vertical bending are derived from an extensive analysis of continuous lifting and lowering-in processes. The stresses from horizontal bending are calculated using closed-form analytical solutions. The tool provides a graphical interface that interprets the background stress analysis results and displays information necessary for the development of lifting and lowering-in plans. The tool can be used to evaluate what-if scenarios for various tentative lifting and lowering-in scenarios. The process of using the tool to develop lifting and lowering-in plans is demonstrated in this paper through an example problem. The number of sidebooms and other lifting and lowering-in parameters such as sideboom spacing and lifting height range are changed to make the lifting and lowering-in plan easy to use for the laying contractors. Such tradeoffs can be addressed proactively with construction contractors to ensure that a mutually acceptable approach to lifting and lowering-in is taken.

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.

A Study of Measurement Methods for Detecting Voiding and Delamination of Die Attach Materials in Power Semiconductor Devices

1996 ◽  
Author(s):  
L. Smith ◽  
T.S. Kalkur
Keyword(s):  
Semiconductor Industry ◽  
Semiconductor Devices ◽  
Electrical Measurement ◽  
Acoustic Microscopy ◽  
Temperature Sensitive ◽  
Analysis Tool ◽  
Electrical Measurements ◽  
X Ray ◽  
Power Semiconductor ◽  
Die Attach

Abstract There are three basic methods used to detect voiding and delamination of die attach materials in semiconductor devices. (1)Electrical measurement of a temperature sensitive parameter (e.g. Vbe, Vgs) under pulsed power conditions is preferred by manufacturers because the data is easily and quickly obtainable during final electrical test; but electrical measurements are only sensitive to gross voiding or delamination. (2)X-ray analysis produces images which are generally accepted as proof of voiding; but X-ray is completely insensitive to delamination or degradation from thermal stress. (3)Use of Scanning Acoustic Microscopy (SAM) as a non-intrusive analysis tool is increasing in the semiconductor industry and provides accurate evidence of delamination in cases where the other two methods fail. The use of all three methods is recommended to maintain a reliable power product fabrication line at its peak of quality with respect to die attach coverage. This paper will compare and contrast the three methods during thermal shock stress in two manufacturer's power Insulated Gate Bipolar Transistor (IGBT) using a lead-tin solder die attach material.

Impact of Die Attach Material and Substrate Design on RF GaAs Power Amplifier Devices Thermal Performance

2001 ◽  
Author(s):  
Victor Adrian Chiriac ◽  
Tien -Yu Tom Lee
Keyword(s):  
Thermal Conductivity ◽  
Layer Thickness ◽  
Power Amplifier ◽  
Thermal Performance ◽  
Metal Layer ◽  
Low Cost ◽  
Organic Substrate ◽  
Die Attach ◽  
Commercial Applications ◽  
The Impact

Abstract The latest commercial applications for microelectronics use GaAs material for RF Power Amplifier devices. This leads to the necessity of identifying low cost packaging solutions with high standards for reliability, electrical and thermal performance. A detailed thermal analysis for the wirebonded GaAs devices is performed using numerical simulations. The main interest of the study focuses on the impact of die attach thermal conductivity (1.0 to 7.0 W/mK), substrate’s top metal layer thickness (25 to 50 μm), and via wall thickness (25 to 50 μm) on GaAs IC device overall thermal performance. The study uses a 2-layer organic substrate; the die attach thickness is 15μm. The peak temperatures reached by PA stages range from 102.7°C to 113.5°C, below the prohibitive/critical value of 150°C (based on 85°C ambient temperature). The increase of die attach thermal conductivity (3 times) led to a slight decrease in peak temperatures (up to 5°C) and the decay is much larger between the cases with 1 and 2.4 W/mK. The largest temperature differences were obtained by varying the thermal via thickness, as opposed to only increasing the top metal layer thickness. The peak temperatures and corresponding junction to ambient thermal resistances are documented. It is determined that for the same die attach thickness, for a thermal conductivity larger than 7 W/mK, the impact on the PA’s peak temperature is insignificant.

An Assessment of the Impact of Interconnect Strategies on Thermal Performance of GaAs Power Amplifier IC Devices

2001 ◽  
Author(s):  
V. H. Adams ◽  
T.-Y. Tom Lee
Keyword(s):  
Thermal Resistance ◽  
Power Amplifier ◽  
Thermal Performance ◽  
Flip Chip ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Printed Circuit ◽  
Wire Bond ◽  
Die Attach ◽  
The Impact

Abstract Alternative interconnect strategies are being considered in place of the standard wire bond interconnect for GaAs power amplifier MMIC devices due to cost and electrical performance improvements. The package/die thermal performance consequences are potentially high-risk issue to these interconnect strategies and requires evaluation. Thermal simulations are conducted to compare and evaluate the thermal performances of three interconnect strategies: wire bond, gold post-flip chip, and through via interconnects. The test vehicle simulated is a three-stage, dual band power amplifier integrated circuit dissipating approximately 5 W steady-state power. Parametric studies are conducted to evaluate the impact of the printed circuit board, die thickness, solid gold vias, and design enhancements on package thermal performance. Best thermal performance is provided by a wire bonded, thin GaAs die attached with solder die attach to a printed circuit board that maximizes the number of plated-through-holes directly under the die. This configuration results in a best case junction-to-heat sink thermal resistance of 12 °C/W. Optimum flip chip and through via designs result in degraded thermal performance compared to the above described wire bond design but may have acceptable thermal performance. For these simulations, predicted junction-to-heatsink thermal resistance is in a range of 15–20 °C/W and is better than a comparable wire bonded design that uses a conductive epoxy die attach material.

Impact of Die Attach Material and Substrate Design on RF GaAs Power Amplifier Devices Thermal Performance

2003 ◽  
Vol 125 (4) ◽  
pp. 589-596 ◽  
Author(s):  
Victor Adrian Chiriac ◽  
Tien-Yu Tom Lee
Keyword(s):  
Thermal Conductivity ◽  
Layer Thickness ◽  
Power Amplifier ◽  
Thermal Performance ◽  
Metal Layer ◽  
Low Cost ◽  
Organic Substrate ◽  
Junction Temperature ◽  
Die Attach ◽  
The Impact

The latest commercial applications for microelectronics use GaAs material for RF power amplifier (PA) devices. This leads to the necessity of identifying low cost packaging solutions with high standards for reliability, electrical, and thermal performance. A detailed thermal analysis for the wirebonded GaAs devices is performed using numerical simulations. The main interest of the study focuses on the impact of die attach thermal conductivity (1.0–50.0 W/mK), substrate’s top metal layer thickness (25–50 μm), and via wall thickness (25–50 μm) on GaAs IC device overall thermal performance. The study uses a two-layer organic substrate. The peak temperatures reached by the PA stages range from 99.6°C to 120.3°C, below the prohibitive/critical value of 150°C (based on 85°C ambient temperature). The increase of die attach thermal conductivity from 1.0 to 7.0 W/mK led to a decrease in peak temperatures of up to 18°C, with larger decay between 1 and 2.4 W/mK. The largest temperature differences were obtained by varying the thermal via thickness, as opposed to only increasing the top metal layer thickness. The peak temperatures and corresponding junction-to-ambient thermal resistances are thoroughly documented. With the same die attach thickness, for a thermal conductivity much larger than 7 W/mK, the impact on the PA’s peak temperature is insignificant. The die attach solder material (with a large thermal conductivity) leads to only a small (2.5°C) decrease in the PA junction temperature.

Ethnogeriatrics: Development and Application of the Cohort Analysis Tool

2014 ◽  
Vol 21 (2) ◽  
pp. 37-52
Author(s):  
Melen McBride
Keyword(s):  
Healthcare Professionals ◽  
Cohort Analysis ◽  
Analysis Tool ◽  
Speech Language Pathology ◽  
Clinical Tool ◽  
Research Activities ◽  
Key Concepts ◽  
Practice Teaching ◽  
Language Pathology ◽  
Significant Factors

Ethnogeriatrics is an evolving specialty in geriatric care that focuses on the health and aging issues in the context of culture for older adults from diverse ethnic backgrounds. This article is an introduction to ethnogeriatrics for healthcare professionals including speech-language pathologists (SLPs). This article focuses on significant factors that contributed to the development of ethnogeriatrics, definitions of some key concepts in ethnogeriatrics, introduces cohort analysis as a teaching and clinical tool, and presents applications for speech-language pathology with recommendations for use of cohort analysis in practice, teaching, and research activities.

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