Thermal Modeling of Plastic Ic Packages

1991 ◽  
Vol 226 ◽  
Author(s):  
A. Bar-Cohen ◽  
Devin E. Mix

AbstractThe successful design of plastic integrated circuit packages for high performance VLSI chips is a crucial element in the development of costeffective packaging technology. Unfortunately, however, most common plastic encapsulating and die-bonding materials provide relatively low thermal conductivities and large thermal expansion coefficients, as well as low mechanical strengths and a limited operating temperature range. These material properties combine to produce a large number of thermally induced package failure modes. Thus, insightful material selection and detailed design, based on extensive thermal modeling/analysis, must be performed to achieve acceptable levels of component reliability.This paper begins with a discussion of the temporal development of the temperature fields inside a plastic IC package and continues with the presentation of transient and steady-state, first-order analytical models for: the chip temperature, the temperature and gradient across the die bond, and the half-thickness encapsulant temperature. The values obtained for a typical PDIP package are discussed and compared to the results of a finite-element analysis of this package. The insights obtained from these analyses are used to develop material Figures-of-Merit that can be used in the selection of die-bond and encapsulant materials for plastic IC packages.

2021 ◽  
Vol 16 (2-3) ◽  
pp. 61-74
Author(s):  
Sahar Ghasemi ◽  
Amir Mirmiran ◽  
Yulin Xiao ◽  
Kevin Mackie

A super lightweight deck can enhance load rating and functionality of a bridge, especially those identified as structurally deficient. This study was aimed to develop and experimentally validate a novel bridge deck as an ultra-lightweight low-profile waffle slab of ultra-high-performance concrete (UHPC) with either carbon fiber reinforced polymer (CFRP) or high strength steel (HSS) reinforcement. The proposed system lends itself to accelerated bridge construction, rapid deck replacement in bridges with load restrictions, and bridge widening applications without the need to replace girders. Performance and failure modes of the proposed deck were initially assessed through extensive lab experiments and finite element analysis, which together confirmed that the proposed deck panel meets the AASHTO LRFD requirements. The proposed deck system is not susceptible to punching shear of its thin slab and fails in a rather ductile manner. To evaluate its long-term performance, the system was further tested under the dynamic impact of wheel load at the Accelerated Pavement Testing (APT) facility of the Florida Department of Transportation using a Heavy Vehicle Simulator (HVS).


Author(s):  
Minshu Zhang ◽  
S. W. Ricky Lee

Interfacial delamination is a long existing problem in the moisture preconditioning process and reflow. The failure is caused by the competition between interfacial strength and hygrothermal stress. Many simulations based on the finite element model have been applied to study the failure mechanism of this phenomenon. However, the difficulty in obtaining material properties of mini-size packages, the lack of experiment investigation of interfacial adhesion and the less-understood moisture analysis will always bring many challenges to simulations. To avoid the above issues, dummy QFN packages were fabricated as the test vehicle for the investigation of the moisture related failure. The major advantage of using dummy packages is that all material properties could be traced and all geometric parameters could be determined without ambiguities. With everything under control, failure modes could be generated within expectation. This would provide a good experiment comparison for future finite element analysis. In this study, several experiment procedures were implemented to establish the relationship between material selection and moisture sensitivity level (MSL) test performance. They were package fabrication, mechanical tests for interfacial adhesion, C-SAM and cross-section inspections. Based on the experimental results, features of the moisture related failure mechanism are presented in this paper.


Author(s):  
Dinesh P. R. Thanu ◽  
Roozbeh Danaei ◽  
Alexander Bermudez ◽  
Sergio A. Chan ◽  
Suzana Prstic

Nowadays microelectronic packaging has become a billion dollar business. Due to the increased material and production costs per package, manufacturing yield loss in this state-of-art business is expected to be at a bare minimum which is tough to persevere in a high volume manufacturing environment. Additionally, high performance and varied power computing needs in the electronic business demands microprocessors with different form factors and complex package designs. One of the most common joint which is extensively used in such a complicated package is the polymer to metal bonding. In the latest technology products involving high package warpage, interfacial bonding has to be strong enough to withstand the dynamic warpage and high mechanical stresses associated with it and hence the reliability of polymer to metal adhesion is critical. In this paper, fundamental mechanisms related to adhesion phenomena of polymer-metal interface are proposed. Adhesive failure modes related to polymer-metal bonding and key variables influencing the bonding of silicone based polymer material to nickel electroplated on copper in an integrated circuit heat spreader assembly are experimentally studied. Factors modulating polymer to metal bonding including interfacial chemistry, surface contamination and material roughness are evaluated.


2016 ◽  
Vol 2016 (1) ◽  
pp. 000524-000528
Author(s):  
Mu-Hsuan Chan ◽  
Yu-Po Wang ◽  
Ivan Chang ◽  
James Chiang ◽  
George Pan ◽  
...  

Abstract Fan-out wafer-level-packaging (FO-WLP) technology has been widely investigated recently with its advantages of thin form factor structure, cost effectiveness and high performance for wide range applications. Reducing wafer warpage is one of the most challenging needs to be addressed for success on subsequent processes. Therefore, the majority of studies focus on the ratio of die and compound thickness, structure design. In order to optimize the warpage for success on subsequent processes, it is indispensable to consider whole wafer process including thermal loading and stress. In this study, reducdution of wafer warpage at each process was proposed in terms of material selection, and process optimization through finite element analysis (FEA) and experiment. Wafer process dependent modeling results were validated by experimental measurement data. The mutual relationship and effects of material property, compound thickness, and corresponding thermal influences were both investigated and addressed. Key parameters were identified based on FEA modeling results: thickness ratio of die/compound andmolding compound materials. Therefore, the geometry design with balanced die/compound ratio is optimal for warpage improvement. The effect of process will be discussed and should be considered for future package warpage characterization. Such findings have been successfully used in process optimization to reduce wafer warapge after grinding process.


2021 ◽  
Author(s):  
Bipin Kashid ◽  
Mitch Eichler

Abstract Engineering simulation has become the pivotal tool for research and development in industries including offshore oil & gas, aerospace, automotive, mobile/off-highway, health care, and others. This case study will explore the financial and time-based savings achieved through detailed simulations and a system-based design approach in two hydraulic valve development projects. The applications in this scope include subsea blowout preventer and off-highway mobile equipment controls. Tools like 1D system simulation, computational fluid dynamics, and finite element analysis are widely accepted; verification and validation (V&V) of these models is imperative in building confidence in simulation. Some V&V reference standards have been developed by groups like ASME and API, but they do not encompass all aspects of simulation regularly utilized by the modern analyst. This places the onus for the creation of V&V guidelines onto individual analysts and their respective employers. Lack of detail in these guidelines can lead to flawed interpretations of results and a corresponding loss of trust in analytical methods. Interdisciplinary organizations can provide forums to help bridge these gaps and create more comprehensive V&V guidelines. Through a study of the development cycles of a subsea valve and an off-highway mobile valve, examples will be outlined which illustrate the benefit of extensive upfront simulation validated by physical testing. Simulation work serves as a cost avoidance measure against many cycles of building and testing prototypes beyond what is truly required in the early stages of design. Accurate simulation is a key component of successful product development, but another often neglected factor is the collaboration between subject matter experts from the component suppliers and the OEM or system integrator. High performance teams comprised of seasoned designers, analysts, and market experts can collaborate to create devices that excel when integrated into a final product. Component designers may wish to isolate the design problem to the component in question, but critical engineering detail will be missed by avoiding a system approach. Expanding the scope of the design analysis to include as much of the application as possible as well as utilizing V&V techniques (beyond minimum industry standards) is key to ensuring that laboratory test data is representative of how a product will perform in its intended application. As the industry continues to evolve, powerful digital twins of systems like blowout preventers can be used for OEM validation of new technology proposed for these systems. However, the fidelity of these digital twins is contingent upon the inputs from thoroughly validated analytical models of the components that comprise the system. By collaborating across the customer-supplier value chain and investing heavily in simulation, offshore manufacturers can strategically position themselves to win in times when both customer expectations and the costs of failure are at an all-time high.


2013 ◽  
Vol 302 ◽  
pp. 212-215
Author(s):  
Xiao Long Wang ◽  
Zhi Luo ◽  
Hong Jie Jing ◽  
Heng An Wu

In the present work, the finite element analysis was employed to study the distribution and level of thermal residual stress generated in matrix reinforced with SO2 nanoparticles. Using Cohesive Element as the bonding of the interface between fiber and matrix, three–dimensional finite element models of periodic cells were established. The results of the models with and without nanoparticles were compared. The residual thermal stressdue to the mismatch of the thermal expansion coefficients between matrix and fibers, especially theshear stress in the interface, decreased with nanoparticles, which could explain the reinforcing mechanism of nanoparticles. Our numerical study can be of great significance in designing new composites with high performance


Author(s):  
Xuefei Shi ◽  
Yi Gao ◽  
Shenghui Cao

<p>This paper mainly studies the bonding mechanism of ribbed steel reinforcing bars in ultra-high performance concrete (UHPC) considering the influence of material ductility. In recent years, the bond slip behavior of reinforcing bars in UHPC has received extensive attention. In the previous pull-out tests, it was found that the classical splitting theory still plays role in bond failure modes. In this paper, the pull-out test is simulated by finite element analysis, and it is found that unlike ordinary concrete, UHPC can still hold the load for a period of time after the tensile stress on splitting surfaces reaches the critical value, due to the ductility of the material. It is found from the numerical results that the bonding stresses are not evenly distributed along the steel bar when the pull-out failure occurred. Through theoretical analysis and experimental verification, the maximum bonding force of ribbed reinforcing bars in UHPC is closely related to the material ductility. Based on this, a new theoretical model for calculating the bonding strength of ribbed steel reinforcing bars in UHPC is proposed, and can be used for the design method of urban bridge built with UHPC.</p>


Author(s):  
S. Khadpe ◽  
R. Faryniak

The Scanning Electron Microscope (SEM) is an important tool in Thick Film Hybrid Microcircuits Manufacturing because of its large depth of focus and three dimensional capability. This paper discusses some of the important areas in which the SEM is used to monitor process control and component failure modes during the various stages of manufacture of a typical hybrid microcircuit.Figure 1 shows a thick film hybrid microcircuit used in a Motorola Paging Receiver. The circuit consists of thick film resistors and conductors screened and fired on a ceramic (aluminum oxide) substrate. Two integrated circuit dice are bonded to the conductors by means of conductive epoxy and electrical connections from each integrated circuit to the substrate are made by ultrasonically bonding 1 mil aluminum wires from the die pads to appropriate conductor pads on the substrate. In addition to the integrated circuits and the resistors, the circuit includes seven chip capacitors soldered onto the substrate. Some of the important considerations involved in the selection and reliability aspects of the hybrid circuit components are: (a) the quality of the substrate; (b) the surface structure of the thick film conductors; (c) the metallization characteristics of the integrated circuit; and (d) the quality of the wire bond interconnections.


2011 ◽  
Vol 39 (3) ◽  
pp. 193-209 ◽  
Author(s):  
H. Surendranath ◽  
M. Dunbar

Abstract Over the last few decades, finite element analysis has become an integral part of the overall tire design process. Engineers need to perform a number of different simulations to evaluate new designs and study the effect of proposed design changes. However, tires pose formidable simulation challenges due to the presence of highly nonlinear rubber compounds, embedded reinforcements, complex tread geometries, rolling contact, and large deformations. Accurate simulation requires careful consideration of these factors, resulting in the extensive turnaround time, often times prolonging the design cycle. Therefore, it is extremely critical to explore means to reduce the turnaround time while producing reliable results. Compute clusters have recently become a cost effective means to perform high performance computing (HPC). Distributed memory parallel solvers designed to take advantage of compute clusters have become increasingly popular. In this paper, we examine the use of HPC for various tire simulations and demonstrate how it can significantly reduce simulation turnaround time. Abaqus/Standard is used for routine tire simulations like footprint and steady state rolling. Abaqus/Explicit is used for transient rolling and hydroplaning simulations. The run times and scaling data corresponding to models of various sizes and complexity are presented.


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