Mathematical modeling of the wall effect on drag forces in molding flow using optical fiber sensing data

Lo, Yu-Lung; Lai, Hsin Yi; Tsai, Ming-Hong

doi:10.1016/s0924-0136(99)00343-x

Cited by 15 publications

(8 citation statements)

References 13 publications

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“…Several drag force models, such as the Lamb, Sherman, and Takaisi model, have been proposed to study the behavior of wire sweep in the encapsulation of semiconductor chips [21]. The conclusion in [22] reveals that the modified Takaisi's model is consistent with the experimental measurement. Therefore, Takaisi's model was adopted in this paper to calculate the drag force of compound flow during the transfer molding process.…”

Section: Numerical Analysismentioning

confidence: 69%

Empirical Equation of Wire Sag Model for Semiconductor Packaging With Numerical and Experimental Verification

Kung

Hsiung

Lee

2013

IEEE Trans. Compon., Packag. Manufact. Technol.

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For the semiconductor packaging industry, the issue of wire sag has not been touched upon because only one single layer of wire bond is constructed along the perimeter of the chip system. Over-sag deflections may not cause any problems. However, driven by the demands for smaller and faster advanced microelectronic devices, modern 3-D and multichip modules have become the solution of choice in delivering higher integration and more multifunctional products to meet consumer needs. For 3-D and multichip packaging, excessive wire sag can lead to wires touching against the lower layer, causing a short-circuit and failure of chip functionality. Therefore, gaining knowledge of wire bond sag theory becomes extremely important for advanced packaging. We propose an empirical model to predict the sag stiffness of a wire bond. The sag stiffness of a wire bond is defined to represent its resistance to the sag drag force occurring during the encapsulation process by the molding flow. A higher sag stiffness of a wire bond gives the premise of less sag deflection, thereby avoiding short-circuiting and/or double wire crosstalk due to the closeness of the top-layer to the bottom-layer wire bonds. The theory of sag regarding semiconductor wire bonding has not been documented, to our knowledge, in the literature. Therefore, to deal with this issue, this paper will primarily focus on the theoretical and numerical analysis of sag deflection of a wire bond. A set of sag experiments is conducted to verify the validity of the sag model hypothesis outlined in the earlier paper. Subsequently, an empirical sag model could be put forward to predict the sag stiffness of a wire bond if the corresponding bond spans, bond heights, and material properties are known. The engineered design of a wire bond can be improved through the use of this sag equation. By making use of the proposed sag model, one can attain not only a first-order estimation of the sag deflection but also omit the tedious procedures of numerical analysis.

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Section: Numerical Analysismentioning

confidence: 69%

Empirical Equation of Wire Sag Model for Semiconductor Packaging With Numerical and Experimental Verification

Kung

Hsiung

Lee

2013

IEEE Trans. Compon., Packag. Manufact. Technol.

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“…These models include Lamb's model, Sherman's model and Takaisi's model [6]. However, based on the conclusions in [12], the three models of drag force were evaluated and revealed that the modified Takaisi's model seems to be consistent with experimental measurement. Therefore, Takaisi's model is adopted in this study to calculate the drag force of compound flow during the transfer molding process.…”

Section: Theoretical Developmentmentioning

confidence: 99%

“…Han and coworkers [10,11] studied drag forces of the gold wire sweep by using a video system and a threestage wire sweep analysis (global-flow analysis, local-flow analysis and wire-sweep deformation analysis) was brought up by them. Lo et al [12] studied the wall effect on drag forces in molding flow using optical fiber sensing data. Their results indicate that the effect of the wall cavity is significant in the calculation of the drag forces and needs to be considered in the transfer molding process.…”

Section: Introductionmentioning

confidence: 99%

The wire sweep analysis based on the evaluation of the bending and twisting moments for semiconductor packaging

Kung

Lee

Wang

2006

Microelectronic Engineering

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“…The drag forces of gold wire sweep were studied using a video system and three-stage wire sweep analysis (global-flow analysis, local-flow analysis and wire-sweep defonnation analysis) was introduced by Han and Wang [7][8]. Lo et al [9] studied the wall effect on viscous forces in molding flow using optical fiber-sensing data. Their results indicate that the effect of the wall cavity is significant in the calculation of the drag forces and needs to be considered in molding.…”

Section: Introductionmentioning

confidence: 99%

The effects of die thickness and bond height on wire sweep in multi-chip module and 3-Dimennsional packages

Chen

Huang

Kung

2008

2008 International Conference on Electronic Materials and Packaging

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Mathematical modeling of the wall effect on drag forces in molding flow using optical fiber sensing data

Cited by 15 publications

References 13 publications

Empirical Equation of Wire Sag Model for Semiconductor Packaging With Numerical and Experimental Verification

Empirical Equation of Wire Sag Model for Semiconductor Packaging With Numerical and Experimental Verification

The wire sweep analysis based on the evaluation of the bending and twisting moments for semiconductor packaging

The effects of die thickness and bond height on wire sweep in multi-chip module and 3-Dimennsional packages

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