• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 184
  • 74
  • 61
  • 38
  • 33
  • 33
  • 28
  • 9
  • 8
  • 5
  • 4
  • 4
  • 3
  • 3
  • 3
  • Tagged with
  • 573
  • 58
  • 53
  • 52
  • 50
  • 43
  • 43
  • 42
  • 37
  • 36
  • 34
  • 31
  • 29
  • 28
  • 28
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Reliability of Wafer-Level CSP Under Cyclic Bending Test

Tsai, Han-Hui 09 July 2004 (has links)
According to the fast development of portable electronic devices, their characteristics are inclined to miniature profile and lightweight. Nowadays, the wafer-level package (WLP) has been widely applied in portable electronic devices for its miniature profile and lightweight. It will become the mainstream trend later soon. The normal use of portable electronic devices brings low-frequency random vibrations to the electronic packages inside. Because of the increasing demand of these devices, the reliability of electronic packages subjected to repeated mechanical loads has become an important issue in the contemporary electronic packaging industry. In this paper both numerical and experimental studies were carried out to investigate the reliability life of Ultra-CSP under cyclic bending conditions. We perform four-point cyclic bending with various combinations of amplitudes and frequencies. Then, we do failure analysis in Ultra-CSP by observing the failure modes. A finite element model for the package is built up for dynamic as well as quasi-static analyses. Accumulated plastic work per bending cycle within the critical solder ball were calculated and together with the experimental results the parameters for the Coffin-Manson fatigue equation were fitted. Through finite element analysis we find that the solder ball which located in the corner has higher accumulated plastic work. Therefore, the crack in the solder ball grew more easily. Thus it lets package resistance rise to determine failure. It was observed from the bending experiments that the influence of frequencies on the fatigue life of the solder interconnects is inapparent. However, influence of amplitude is significant. From the results of both experiments and FEA, it was found that for this particular ultra-CSP specimen under cyclic bending conditions, the characteristic life was expressed as
82

JEDEC standard board level drop test on lead-free packages

Chen, Chien-ming 07 July 2005 (has links)
Solder joints are the most fragile parts in electronic package. The properties of joints made of lead-free material are harder and crisper than those of lead-contained material. They tend to break due to dynamic loading by absorbing the impact energy and result in malfunction. Thus, how to improve the reliability of contact joints made of lead-free material in dynamic loading has become an important topic for research. This work is based on JEDEC Standard JESD22 - B111 ¡§Board Level Drop Test Method of Components for Handheld Electronic Products,¡¨ and JESD22 ¡V B110 ¡§Subassembly Mechanical Shock¡¨. The setup of drop test apparatuses was used to conduct dropping tests with the impact of acceleration 1500 G, in order to acquire the reliability of SnAgCu, SnCu, and SnAg alloy, which would be compared with 63Sn37Pb. The specimens would be red-dyed for an analysis under SEM to examine the distribution of the breakage. The results were analyzed by Weibull distribution to predict Mean Time to Failure (MTTF), it is revealed that MTTF of solder joints made of Sn0.7Cu, Sn2.6Ag0.5Cu, and Sn3.0Ag0.5Cu (MTTF=355.32, 295.82, 289.54 cycles respectively) are longer than that made of 63Sn37Pb (MTTF=152.52 cycles). Notably, MTTF of alloy Sn0.7Cu is 2.3 times of solder joints of SnPb. Alloy Sn3.0Ag0.5Cu has the shortest MTTF among the three, which is also 1.89 times of alloy SnPb. That is to say, under impact of 1500G, solder joints made of Sn0.7Cu, Sn2.6Ag0.5Cu, and Sn3.0Ag0.5Cu possess greater resistance to shock than alloy 63Sn37Pb, which is in common by used at present. In addition, the breakage of solder joints mainly generated on Intermetallic Compound (IMC) and around the four corners, distributed from the periphery to the central area. Especially, those on the corners receive greater stresses due to edge effect.
83

Design and Implementation of HBT MMICs for W-CDMA Applications Including Evaluation of Package and PCB Effects

Wu, Jian-Ming 08 June 2006 (has links)
This research aims to design and implement GaAs HBT MMICs for the two crucial components in W-CDMA transmitters, quadrature modulator and upconverter, with thorough evaluation of the package and PCB effects. To construct a strong theoretical foundation, the small-signal modeling of HBTs and the EM-characterization of package and PCB interconnects are intensively studied. In this dissertation, a novel extrinsic-inductance independent approach is developed for direct extraction of the intrinsic elements in a hybrid-pi equivalent circuit of HBTs. The interconnects of leadless RFIC packages and test PCBs are investigated using the 3-D EM simulation tools and transformed into the equivalent circuits for co-analysis with the designed HBT MMICs. The first HBT MMIC design is a W-CDMA direct-conversion quadrature modulator incorporating a new 90 degrees phase shifter. Although the proposed 90 degrees phase shifter has a remarkable advantage over the others in implementation loss, it is rather susceptible to the package and PCB effects, resulting in a moderate degradation of EVM. The second HBT MMIC design is a W-CDMA upconverter incorporating a popular micromixer. Although the micromixer-based upconverter consumes much less current at low output powers to achieve the same high linearity when compared to a Gilbert mixer-based design, it is quite susceptible to the package and PCB effects, causing a significant degradation in ACPR. Comparison between theory and measurement shows good agreement in evaluating the influences of package and PCB interconnects on both HBT MMICs.
84

The Study on the Measurement of Out-of-Plane Displacement of an Object Subjected to Both Temperature and Displacement Field by Using the Holographic Interferometry

Tsai, Ming-Lang 17 May 2001 (has links)
The main aim of this study is to extending the holographic interferometry technique to measure the out-of-plane displacement of an object subjected to both temperature and displacement field. It is noted that both the out-of-plane displacement and the ambient temperature change can cause image fringes. Therefore, an auxiliary object is used to identify the fringe numbers caused by the ambient temperature change during the experiment. The warpage measurement of a PBGA package is used as an example. It can be shown that the proposed method works
85

The Effect of Chloride Ion and Copper Oxide Layer on Plastic-encapsulated Package Reliability

Huang, Sheng-Tzung 20 June 2001 (has links)
None
86

Analysis on the Characteristics of IC Package

Tsai, Ching-Liang 22 June 2001 (has links)
To calculate the characteristics of electronic parts is divided by 1.Chip. 2.Assembly, i.e. package. 3. PCB (Printed Circuit Board). Analizing the electrical characteristics of package needs consideration from all system can distinguish the influence of function. Although the analysis method may be change but we can get the characteristics results from the parameters of circuit element (i.e. Resistance, Inductance, Capacitance). Different measurement or modeling technology can prove that the list data is correct. That moisture in plastic packages can cause cracking or delamination during the surface mount assembly process. During this process, the packages are heated to 220-240¢J. At these temperatures, any moisture present in the plastic vaporizes and exerts stresses in the package, which can cause delamination between the mold compound and the leadframe or die. The mismatch in thermal expansion coefficients of the package¡¦s components also induces stresses. If these combined stresses are greater than the fracture strength of the plastic, cracks will form. The susceptibility of a package to cracking depends on: 1.amount of absorbed moisture, 2.die size, 3.package design, 4.mold compound characteristics, 5.solder reflow temperature profile. Widely, flip chip technology is defined as mounting the chip to a substrate with any kind of materials and methods, as long as the chip surface (active area) is facing to the substrate. The advantages of FC-BGA is¡G1.Efficient use of PCB area. 2.Area array access for high I/O device. 3.Allow for finer pitches. 4.Fewer joints. 5.Better performance of high frequency application. 6.FC is and will be lowest cost.
87

Investigation of Package Parasitic on the Performance of SAW Filter

Lin, Kuan-Yu 08 July 2002 (has links)
Because SAW filters are small, high reliability, and it cannot be easily integrated with silicon substrate, they have become one of the most popular communication passive components recently. As the working frequency becomes higher, SAW filters are more sensitive to electromagnetic interference introduced by the package. Discrepancy in performance between design and measurement can be large if the packing effects are not considered. In this thesis, we make use of Finite Difference Time Domain method (FDTD) and develop a procedure combining High Frequency Structure Simulator (HFSS) with ADS software to simulate electromagnetic effect of a packaged SAW Filter. This is a full-wave method that integrates electromagnetic wave and acoustic wave. Measurement is also carried out to verify the simulated results. Preliminary results show that this method that we provide can predict frequency response in package effectively. Our Prediction can save factory design time and production cost.
88

Package Implementation : A Methodology For Requirement Gap Analysis

Hsu, Cheng-Yi 24 June 2003 (has links)
The global business is facing the intensive competitive environment. To overcome the competition, most enterprises contentiously try different information systems to strengthen their competition and to extent their businesses. In order to execute the enterprises marketing strategies effectively, business organization applies various software from in-house development to standard package software either made in Taiwan or made in nations. However, while implementing the information system into specific project, this software caused many obstructions in both project time framing design and project cost control. To exam this problem, we found there is no appropriate requirement and package software or tool to manage the system gaps analysis. The main purpose of this thesis is to solve the present package software problem and develop a method to meet the enterprise needs in system difference analysis. We use the Unified Module Language (UML), use case diagram, drawing , activity diagram, use case description and decision table to complete the difference analysis between package software and specific project. Applying this method, the user not only can control the difference between the requirement system and object system precisely, but also build a communication channel among the users, system analysis, and programmers. In addition, the method provides a trend of customized system to succeed the project on line
89

Package Implementation: A Study of Data and Output Misfits Identification

Wu, Chi-cheng 30 June 2003 (has links)
Three categories of misfit have been identified in the software package implementation context. They are Data, Functional, and Output misfits. This study presents a methodology, based on the business form analysis and SEMINT technique, to help identify the Data and Output misfits. With this methodology, the software package acquiring organizations or consulting firms can more easily and systematically identify where the Data and Output misfits are and what the degree of misfits is. These results can contribute to the selection of a suitable software package and are valuable to the decision of either package customization or business process reengineering for the misfits during the package implementation.
90

The Effects of Package Design and Brand Image on Consumers¡¦ Purchase Intention ¡Ð Packaged Tea as an Example

Ko, Ding-fu 16 June 2009 (has links)
The latest data reveals, in 2008, the total market value of tea beverage in Taiwan exceeded 20 billion NT dollars. Because the tea beverage market is extremely large, there are dozens of brands in the market. When a customer wants to choose a product from kinds of choices, what factors does he/she consider? According to former research, we know that the factors include price, brand, package design, sales promotion and advertisement. However, we still didn¡¦t know how they affect consumers buying tea beverage. Consequently, this study researched that if both package design and brand image have notable influences on consumers¡¦ purchase intention for packaged tea by regression analysis. The major results for the research are as follows: 1.Approximate 90% of respondents usually buy packaged tea in convenient stores. Half of them indicate that their motivations of buying packaged tea are thirst-quenching. More than half of respondents buy Uni-president most frequently, and then is Vitalon. 2.This study uses two tea brands as subjects to test the hypothesis repeatedly. The results revealed that package design have notable influence on purchase intention. So, manufacturers should change the package design irregularly and try to analyze the merits and drawbacks to improve the package. 3.The results also revealed that brand image have notable influence on purchase intention. It represents that brand image play a significant role in a consumer¡¦s purchasing process. Manufacturers should pass through the basic threshold, or their products would not be acceptant by consumers.

Page generated in 0.0374 seconds