Yung-Yu Hsu

Feng Chia University, 臺中市, Taiwan, Taiwan

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Publications (5)1.12 Total impact

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    ABSTRACT: This paper aims at developing an effective scheme for design optimization of a novel nanocomposite-typed flip chip (FC) technology, constructed by integrating an Ag-nanowire/polymer nanocomposite film together with a nonconductive paste (NCP) technology. The objective of the optimization problem is to achieve the optimal process-induced thermal-mechanical behaviors of the novel FC technology during the NCP bonding process through the selection of material properties, process parameters and geometry data. The process-induced thermal-mechanical behaviors are evaluated using a process-dependent simulation methodology that integrates both transient thermal and nonlinear contact FE analyses and a “death-birth” meshing scheme. The validity of the process-dependent FE simulation methodology is also confirmed through experiment. To demonstrate the effectiveness of the present design optimization approach, several design problems associated with the FC technology are performed.
    Microsystems, Packaging, Assembly and Circuits Technology Conference, 2009. IMPACT 2009. 4th International; 11/2009
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    ABSTRACT: Extensive understanding and management of the thermal-mechanical characteristics of novel packaging designs during the bonding process are indispensable to the realization of the technologies. Thus, this paper attempts to explore the bonding process-induced thermal-mechanical behaviors of an advanced flip chip (FC) electronic packaging. FC packaging employs a novel anisotropic conductive film, which is a thin composite film composed of polymer matrix and thousands of millions of highly oriented, 1-D silver (Ag) nanowires on the scale of 200 nanometers in diameter. For carrying out the process simulation, a process-dependent finite element (FE) simulation methodology that integrates both thermal and nonlinear contact FE analyses and a special meshing scheme is applied. The material properties of the nanoscale Ag wires are first explored using molecular dynamics (MD) simulations. By the characterized material properties of the Ag nanowires, the effective material properties of the composite film are derived through two theoretical approaches: 1) the rule-of-mixture (ROM) technique and 2) the proposed FE method-based approach. The predicted results by these two approaches are extensively compared with each other to examine the feasibility of using the widely used ROM technique for such cases. In addition, the validity of the proposed process-dependent FE simulation methodology is also confirmed through three experiments: 1) micro-thermocouple measurement of temperature; 2) Twyman-Green Moire interferometry measurement of out-of-plane deformations; and 3) portable engineering Moire interferometry measurement of in-plane deformations. Throughout the investigation, the effectiveness of the novel interconnect technology is demonstrated. Good agreement with the experiments is also obtained. It is found that the technology may ensure good electrical performance and structural integrity, not only at room temperature but even at elevated temperature, based on its substantial c- - ontact stresses but minor peeling stresses on the bonding line, together with a moderate, process-induced warpage on the substrate.
    IEEE Transactions on Advanced Packaging 06/2009; · 1.12 Impact Factor
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    ABSTRACT: As the prediction that the I/O pitch will decrease from 60 um in 2004 to 20 um beyond 2010 by ITRS roadmap, flip chip interconnection by traditional ACF containing conductive particles with micro-meter size will face more and more challenges. One of many possible solutions is using high aspect-ratio metal posts or flake instead of conductive particles for electrical interconnection between chip and substrate. But this interconnection by metal posts is less reliable compared with elastic conductive particles. Therefore we develop a new type of conductive film composed of nanowires and polymer. Unlike some other composed material by blending nanowires, tubes, powders in polymer, the arrangement of nanowires in polymer is highly ordered in X, Y, and Z direction for anisotropic conductance. In order to achieve high reliability performance of this novel package, the structure design of flip chip package constructed by nanowires/polymer conductive film was evaluated by stress simulation and related D.O.E analysis. In this research, series of finite element models were established based on the D.O.E. (design of experiment) matrix. The four factors including thickness of nanowires/polymer composed film, volume ratio of nanowires in nanowires/polymer composed film, CTE and Young's modulus of polymer were used in this D.O.E. matrix. The full factorial DOE matrix was applied to optimize the response of peeling stress. These results indicated that volume ratio of nanowires was the major factor. The other important factor was film thickness. Besides the above stress analysis, we also demonstrated the production of nanowires/polymer composed film. Now we can obtain the silver nanowires/polyimide composed films with diameter of nanowire about 200nm and maximum film thickness up to 50 um. The X-Y insulation resistance is about 4~6 GOmega and Z-direction resistance including the trace resistance (3mm length) is less than 0.2Omega
    Electronics Packaging Technology Conference, 2004. EPTC 2004. Proceedings of 6th; 01/2005
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    ABSTRACT: First Page of the Article
    Electronic Components and Technology Conference, 2005. Proceedings. 55th; 01/2005
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    ABSTRACT: As microelectronic packaging industry grows explosively, high I/O density interconnects and reliable packaging design are recognized as the main concern of the IC packaging industry. Hence, in this investigation, a novel type of anisotropic conductive film (ACF) composed of cobalt nanowires and polymer was developed and used in place of conventional solder bumps for ultra-fine pitch interconnect. Unlike some other ACF materials that blend either nanowires, tubes, or powders in polymer, the nanowires entrenched in polymer is well aligned in one direction so as to achieve high anisotropic conductance. Basically, the material properties of the nanowire/polymer-based conductive film would have a great effect on the thermal-mechanical behaviors of the technology, which would generally lead to a reliability issue. Thus, the underlying goal of the study was to characterize the out-of-plane mechanical properties, including reduced modulus and hardness, through a nanoindentation technique. The tip of nanoindentation was 300nm in diameter and measured method was force-control. Results show that the mean value of the reduced-modulus of the film is 14.471GPa at a standard deviation of 2.578GPa. These statistical results were based on 102 data points with high consistency.