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전자패키징 접속재료용 이방성 전도 접착제의 열/기계적/전기적 거동 및 신뢰성에 관한 연구
No full text학위논문(박사) - 한국과학기술원 : 신소재공학과, 2005.8, [ xv, 179 p. ]In this study, electro-thermo-mechanical responses of anisotropic conductive adhesive materials and assembly reliability were investigated.
A number of studies have turned their attention to the development of contact models for understanding the ACA interconnects. Chapter Two introduces an experimental technique developed to allow continuous monitoring of deformation characteristics of a single conductive particle. The load-deformation curve of single conductive particle is accurately measured, which provide (1) the accurate force vs. deformation relation of single conductive particle, (2) elastic recovery characteristics, and (3) basic information for the deformation of multi-particles system on bumps. Based on the deformation behaviors of each conductive particle, mechanical and electrical properties of ACA joint were discussed to improve the bonding quality and reliability.
Chapter Three presents the thermal and mechanical contribution of anisotropic conductive films (ACFs) to the electrical conduction establishment of ACF joint. In this part, ACF flip chip process is fully designed based on the material characterization and in-situ process monitoring. Moreover, the effect of degree of cure on the ACF conduction establishment is investigated in a bonding process window. The build-up shrinkage stress for the conduction establishment is experimentally considered with thermo-mechanical measurement of ACF.
Chapter Four discusses the importance of the mechanism of shrinkage and contraction stress and the relationship between these mechanisms and the thermo-mechanical properties of ACFs. Both thickness shrinkages and modulus changes of four kinds of ACFs with different thermo-mechanical properties are experimentally investigated with thermo-mechanical and dynamic mechanical analysis. Based on the incremental approach to linear elasticity, contraction stresses of ACFs developed along the thickness direction are estimated. In this contribution, we establish a metho...한국과학기술원 : 신소재공학과
Chip warpage model for reliability prediction of delamination failures
No full textA new experimental method to predict reliability for ACA type packages under temperature cycling is developed and proposed. The method introduces a new damage parameter that can be easily measured by experiment. It is proved that the linear elastic parameter, dw/dT which represents the rate of change of chip warpage with respect to temperature, efficiently reflects the common failure mechanism of ACA type packages, the interfacial delamination between the chip and the adhesive. It is demonstrated, both experimentally and numerically, that the size of delamination affects the warpage behavior of the chip. The dw/dT of the chip is monitored in real time using laser interferometers under thermal fatigue cycles up to 3000. The gradual decrease in warpage due to progressive increase in delamination is clearly emerged. As a result, a reliability curve that can predict the size of delamination and remained life is obtained. The new long-term reliability prediction method developed in this study can be applied to various advanced packages, e.g. underfilled flip-chip or TSV stacked chip packages, that embrace interfacial delamination as primary failure mode. (C) 2011 Elsevier Ltd. All rights reserved
고주파 플립 칩 패키지 애플리케이션을 위한 전도성 접착제 제조 방법
No full textDisclosed is a method for manufacturing a low dielectric constant conductive adhesive that is appropriate for a radio frequency packaging application. This method is characterized by mixing a thermosetting resin with surface-treated conductive particles and non-conductive particles for prevention of agglutination and thereby forming the conductive adhesive. The manufactured conductive adhesive is useful for a bonding material of the radio frequency packaging. According to the present invention, it is possible to obtain a flip chip bonding having superior mechanical and electrical performance compared with the conventional flip chip bonding art. Also, since the adhesive has a low high frequency loss and a low dielectric constant, it is possible to realize a flip chip package having a superior electrical performance. The conductive adhesive is particularly useful for the flip chip packaging of a device having a bandwidth of microwave and millimeter wave
Microwave frequency model of FPBGA solder ball extracted from S-parameters measurement
No full textFirst we introduce the high-frequency equivalent circuit model of the Fine Pitched Ball Grid Array (FPBGA) bonding for frequencies up to 20 GHz. The lumped circuit model of the FPBGA bonding was extracted based on S-parameters measurement and subsequent fitting of the model parameters. The test packages, which contain probing pads, coplanar waveguides and FPBGA ball bonding, were fabricated and measured. The suggested pi-model of the FPBGA bonding consists of self-inductor, self-capacitor, and self-resistor components. From the extracted model, a solder ball of 350mum diameter and 800mum ball pitch has less than 0.08 nH self-inductance, 0.40 pF self capacitance, and about 10 mOmega self-resistance. In addition, the mutual capacitance caused by the presence of the adjacent bonding balls is included in the model. The FPBGA solder ball bonding has less than 1.5 dB insertion loss up to 20 GHz, and it causes negligible delay time in digital signal transmission. The extracted circuit model of FPBGA bonding is useful in design and performance simulation of advanced packages, which use FPBGA bonding.This work was supported by Center for Electronic Packageing Materials of Korea Science and Engineering Foundation
Contraction stresses development of anisotropic conductive films (ACFs) flip chip interconnection: Prediction and measurement
No full textIn this study, the buildup of contraction stresses and the effect of anisotropic conductive film (ACF) properties on contraction stresses were investigated. Both ACF thickness shrinkage and modulus change of four kinds of ACFs with different thermomechanical properties were experimentally investigated using thermomechanical and dynamic mechanical analysis. Based on an incremental approach to linear elasticity, the contraction stresses of ACFs developed along the thickness direction were numerically predicted. In addition, the contraction stresses of ACFs were developed during the cooling process from the glass transition temperature of ACFs to room temperature. The buildup of contraction stresses below T-g was strongly dependent on both the coefficient of thermal expansion (CTE) and elastic modulus (E) of ACFs. A nanoscale deformation field of thin ACF layers was obtained to measure the contraction stresses experimentally using a phase shifting moire technique. Good agreement between the contraction stresses predicted from the incremental approach and the actual vertical stresses measured from a phase shifting moire analysis was obtained. Therefore, the full temperature-evolution of contraction stresses based on the incremental approach to linear elasticity is reliable and thereby can be used to predict the contraction stress behavior of polymeric ACF materials
Effects of Silica Filler and Diluent on Material Properties of Non-Conductive Pastes and Thermal Cycling Reliability of Flip Chip Assembly
No full textIn this paper, thermo-mechanical and rheological properties of NCPs (Non-Conductive
Pastes) depending on silica filler contents and diluent contents were investigated. And then, thermal
cycling (T/C) reliability of flip chip assembly using selected NCPs was verified. As the silica filler content
increased, thermo-mechanical properties of NCPs were changed. The higher the silica filler content was
added, glass transition temperature (Tg) and storage modulus at room temperature became higher. While,
coefficient of thermal expansion (CTE) decreased. On the other hand, rheological properties of NCPs were
significantly affected by diluent content. As the diluent content increased, viscosity of NCP decreased
and thixotropic index increased. However, the addition of diluent deteriorated thermo-mechanical
properties such as modulus, CTE, and Tg. Based on these results, three candidates of NCPs with various
silica filler and diluent contents were selected as adhesives for reliability test of flip chip assemblies. T/
C reliability test was performed by measuring changes of NCP bump connection resistance. Results
showed that flip chip assembly using NCP with lower CTE and higher modulus exhibited better T/C
reliability behavior because of reduced shear strain in NCP adhesive layer
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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