Microwave Frequency Model of FPBGA Solder Ball Extracted from S-Parameters Measurement

Junho LEE  Seungyoung AHN  Woon-Seong KWON  Kyung-Wook PAIK  Joungho KIM  

IEICE TRANSACTIONS on Electronics   Vol.E87-C   No.9   pp.1621-1627
Publication Date: 2004/09/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Electronic Components
ball grid array,  fine pitched BGA,  lumped circuit model,  microwave frequency,  S-parameters,  

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First 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 π-model of the FPBGA bonding consists of self-inductor, self-capacitor, and self-resistor components. From the extracted model, a solder ball of 350 µm diameter and 800 µm ball pitch has less than 0.08 nH self-inductance, 0.40 pF self capacitance, and about 10 mΩ 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.