• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.7
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• pp.339-342
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• 2005

We present a new high-frequency equivalent circuit model for 52pin QFP used in typical IC's and extract R, L, and C values of this circuit model using a 3-D E & M field simulator. Futhermore, L and C value variations as a function of Pin number due to the shape differences of the leads have been fitted to 2nd order polynomials in order to extend the applicability of this model.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.437-438
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• 2010

• Proceedings of the KWS Conference
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• 1997.05a
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• pp.165-168
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• 1997

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.5
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• pp.151-156
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• 2007

In this paper, the creep characteristics of lead and lead-free solder joint were investigated using the QFP(Quad Flat Package) creep test. Two kind of solder pastes(Sn-3Ag-0.5Cu, Sn-0.2Sb-0.4Ag-37.4Pb) were applied to the QFP solder joints and each specimen was checked the external and internal failures(i.e., wetting failure, void, pin hole, poor-heel fillet) by digital microscope and X-ray inspection. The creep test was conducted at the temperatures of $100^{\circ}C$ and $130^{\circ}C$ under the load of 15$\sim$20% of average pull strength in solder joints. The creep characteristics of each solder joints were compared using the creep strain-time curve and creep strain rate-stress curves. Through the comparison, the Sn-3Ag-0.5Cu solder joints have higher creep resistance than that of Sn-0.3Sb-0.4Ag-37.4Pb. Also, the grain boundary sliding in the fracture surface and the necking of solder joint were observed by FE-SEM.

• Journal of the Semiconductor & Display Technology
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• v.10 no.4
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• pp.37-42
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• 2011

In this paper, novel carbon nanotube (CNT)-filled Solderable electrically conductive adhesive (ECA) and joining process have been developed. To investigate the bonding characteristics of CNT-filled Solderable ECA, three types of Solderable ECAs with different CNT weight percent (0, 0.1, 1wt%) were formulated. For a joining process, the quad flat package (QFP) chip was used. The QFP chip had a size of $14{\times}14{\times}2.7$ mm and a 1 mm lead pitch. The test board had a Cu daisy-chained pattern with 18 ${\mu}m$ thick. After the bonding process, the bonding characteristics such as morphology of conduction path, electrical resistance and pull strength were measured for each formulated ECAs. As a result, the electrical and mechanical bonding characteristics for a QFP joints using CNT-filled ECA were improved about 10% compared to those of QFP joints using ECA without CNT.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2004.11a
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• pp.74-74
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• 2004

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.917-918
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• 2009

• Proceedings of the KWS Conference
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• 2006.10a
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• pp.184-186
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• 2006

Sn-3Ag-0.5Cu is one of candidate as an alternative approach to conventional lead-tin solder. In order to evaluate that creep characteristic of QFP, we used Sn-3Ag-0.5Cu where the operating temperature is $100^{\circ}C$. The specimens were loaded to failure at average pull strength in the range of 20% to 25%, X-ray machine is used to eliminate effect of void. In this paper, relation of time-displacement and steady state creep rate was studied, and used to analyze the experimental result.

• Laser Solutions
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• v.2 no.1
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• pp.38-42
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• 1999

As very large scale integration technology has been developed, much more accurate, reliable technology is needed for outer lead bonding. Laser soldering has been researched as an alternative for fine pitch device bonding. This study is focused on how to select optimal laser soldering variables with which solder wets parent material, the microstructural results of laser soldering and the reliability test One of popular packages, QFP100 was soldered successfully with two kinds of solder. The inspection of the joint for reliability was carried out by optical microscope, SEM, EDAX and pull test, which demonstrated the superiority of laser soldering.

• Proceedings of the KWS Conference
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• 2006.05a
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• pp.329-331
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• 2006