• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.10
• /
• pp.183-190
• /
• 2003

Major device failures such as die cracking, interfacial delamination and warpage in flip chip packages are due to excessive heat and thermal gradients- There have been significant researches toward understanding the thermal performance of electronic packages, but the majority of these studies do not take into account the combined effects of thermo-mechanical interactions of the different package constituents. This paper investigates the thermo-mechanical performance of flip chip package constituents based on the finite element method with thermo-mechanically coupled elements. Delaminations with different lengths between the silicon die and underfill resin interfaces were introduced to simulate the defects induced during the assembly processes. The temperature gradient fields and the corresponding stress distributions were analyzed and the results were compared with isothermal case. Parametric studies have been conducted with varying thermal conductivities of the package components, substrate board configurations. Compared with the uniform temperature distribution model, the model considering the temperature gradients provided more accurate stress profiles in the solder interconnections and underfill fillet. The packages with prescribed delaminations resulted in significant changes in stress in the solder. From the parametric study, the coefficients of thermal expansion and the package configurations played significant roles in determining the stress level over the entire package, although they showed little influence on stresses profile within the individual components. These observations have been implemented to the multi-board layer chip scale packages (CSP), and its results are discussed.

• Proceedings of the International Microelectronics And Packaging Society Conference
• /
• 2002.05a
• /
• pp.138-141
• /
• 2002

There are continuous efforts in the electronics industry to a reduced electronic package size. Reducing the size of electronic packages can be achieved by a variety of means, and for ball grid array(BGA) packages an effective method is to decrease the pitch between the individual balls. Chip scale package(CSP) and BGA are now one of the major package types. However, a reduced package size has the negative effect of reducing board-level reliability. The reliability concern is for the different thermal expansion rates of the two-substrate materials and how that coefficient CTE mismatch creates added stress to the BGA solder joint when thermal cycled. The point of thermal fatigue in a solder joint is an important factor of BGA packages and knowing at how many thermal cycles can be ran before failure in the solder BGA joint is a must for designing a reliable BGA package. Reliability of the package was one of main issues and underfill was required to improve board-level reliability. By filling between die and substrate, the underfill could enhance the reliability of the device. The effect of underfill on various thermomechanical reliability issues in $\mu$BGA packages is studied in this paper.

• Journal of Digital Convergence
• /
• v.11 no.10
• /
• pp.47-57
• /
• 2013

Big data analysis needs a new tool for decision making in view of data volume, speed, and variety. Many global IT enterprises are announcing a variety of Big data products with easy to use, best functionality, and modeling capability. Big data packages are defined as a solution represented by analytic tools, infrastructures, platforms including hardware and software. They can acquire, store, analyze, and visualize Big data. There are many types of products with various and complex functionalities. Because of inherent characteristics of Big data, selecting a best Big data package requires expertise and an appropriate decision making method, comparing the selection problem of other software packages. The objective of this paper is to suggest a decision making method for selecting a Big data package. We compare their characteristics and functionalities through literature reviews and suggest selection criteria. In order to evaluate the feasibility of adopting packages, we develop two Analytic Hierarchy Process(AHP) models where the goal node of a model consists of costs and benefits and the other consists of selection criteria. We show a numerical example how the best package is evaluated by combining the two models.

• Journal of the Microelectronics and Packaging Society
• /
• v.29 no.3
• /
• pp.43-48
• /
• 2022

In this study, simulation method was developed to improve the accuracy of the warpage simulation based on the equivalent anisotropic viscoelastic model. First, a package with copper traces and bumps was modeled to implement anisotropic viscoelastic behavior. Then, equivalent anisotropic viscoelastic properties and thermal expansion coefficient for the bump region were derived through the representative volume element model. A thermal cycle of 0 to 125 degrees was applied to the package based on the derived mechanical properties, and the warpage according to the thermal cycle was simulated. To verify the simulation results, the actual package was manufactured, and the warpage with respect to the thermal cycle was measured through shadow moiré interferometer. As a result, by applying the equivalent anisotropic viscoelastic model, it was possible to calculate the warpage of the package within 5 ㎛ error and predict the shape of the warpage.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.6 no.4
• /
• pp.384-389
• /
• 1982

It is necessary that machine tool structures should be designed so that they will cause a minimum chance of machining chatter. In order to do this, a computer program package is developed utilizing Finite Element Method, modal flexibility and energy balance method. Validity of the program package is verified through computer simulation analysis and impulse test of a simplified machine tool structure.

• Korean Management Science Review
• /
• v.10 no.2
• /
• pp.79-91
• /
• 1993

Strategic decisions related to the design of a physical distribution system can be classified into three basic components : facility location, transportation, inventory decisions. In this research the interdependence of those decisions are expressed in a mathematical model such that the total relevant cost of the system is minimized. We suggested a heuristic technique for solving the model. In broad terms, our solution technique combines a heuristic method for determining which candidate DCs to open and an exact method for minimizing costs given a set of open DCs. And we also developed a decision supporting package for the design of a physical distribution system.

• Proceedings of the Korea Association of Information Systems Conference
• /
• 2001.12a
• /
• pp.158-165
• /
• 2001

The certification of software products can provide a greater level of acceptance and feeling of security to customers of these products. This paper presents a certification method for the quality of package software. First of all, the evaluation criteria are derived from ISO/1EC 9126 and 12119 standards, and then the evaluation module are designed considering the measurement scale type. The results can be applied to construct the certification scheme of software product quality for the commercial purpose.

• 제어로봇시스템학회:학술대회논문집
• /
• 1986.10a
• /
• pp.5-8
• /
• 1986

The simulation algorithm for all kinds of robots with arbitrary degrees of freedom which are combined with revolute joints or prismatic joints, or combinations was studied and implemented. This simulation package is composed of trajectory planning routine, control routine, kinematics routine using Newton-Raphson method, dynamics based on Newton-Euler method with four-bar linkage analysis, input routine and output routine.

• Journal of the Korea Safety Management & Science
• /
• v.4 no.1
• /
• pp.93-103
• /
• 2002

The certification of software products can provide a greater level of acceptance and feeling of security to customers of these products. This paper presents a certification method for the quality of package software. First of all, the evaluation criteria are derived from ISO/IEC 9126 and 12119 standards, and then the evaluation module are designed considering the measurement scale type. The results can be applied to construct the certification scheme of software product quality for the commercial purpose.

• Journal of the Microelectronics and Packaging Society
• /
• v.9 no.2
• /
• pp.33-38
• /
• 2002

High performance packages must have a minimum insertion loss and return loss. In this paper, we design a millimeter-wave ceramic package using LTCC (Low Temperature Cofired Ceramic) technology to satisfy excellent transmission characteristics and characterize in a frequency range from DC to 30 GHz using the FEM (Finite Element Method) calculation. From these calculation results, the designed feed-through structure achieved 0.32 dB, 16.8 dB of the insertion loss and the return loss at 30 GHz respectively. This designed ceramic package will be useful for MMIC (Monolithic Microwave Integrated Circuit) modules.