Heat transfer and deformation analysis of flexible printed circuit board under thermal and flow effects

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<jats:title content-type="abstract-subheading">Purpose</jats:title>
<jats:p>The purpose of this study is to investigate heat transfer and deformation of flexible printed circuit board (FPCB) under thermal and flow effects by using fluid structure interaction. This study simulate the electronic cooling process when electronic devices are generating heat during operation at FPCB under force convection.</jats:p>
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<jats:title content-type="abstract-subheading">Design/methodology/approach</jats:title>
<jats:p>The thermal and flow effects on FPCB with attached ball grid array (BGA) packages have been investigated in the simulation. Effects of Reynolds number (<jats:italic>Re</jats:italic>), number of BGA packages attached, power supplied to the BGA packages and size of FPCB were studied. The responses in the present study are the deflection/length of FPCB (<jats:italic>δ/L</jats:italic>) and Nusselt number (<jats:italic>Nu</jats:italic>).</jats:p>
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<jats:title content-type="abstract-subheading">Findings</jats:title>
<jats:p>It is important to consider both thermal and flow effects at the same time for understanding the characteristic of FPCB attached with BGA under operating condition. Empirical correlation equations of <jats:italic>Re</jats:italic>, Prandtl number (<jats:italic>Pr</jats:italic>), <jats:italic>δ/L</jats:italic> and <jats:italic>Nu</jats:italic> have been established, in which the highest effect is of <jats:italic>Re</jats:italic>, followed by <jats:italic>Pr</jats:italic> and <jats:italic>δ/L</jats:italic>. The <jats:italic>δ/L</jats:italic> and <jats:inline-formula id="ueq55">
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<m:math xmlns:m="http://www.w3.org/1998/Math/MathML" display="block"><m:mrow><m:mover accent="true"><m:mrow><m:mi>N</m:mi><m:mi>u</m:mi></m:mrow><m:mo stretchy="true">¯</m:mo></m:mover></m:mrow></m:math></jats:inline-formula> were found to be significantly affected by most of the parametric factors.</jats:p>
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<jats:title content-type="abstract-subheading">Practical implications</jats:title>
<jats:p>This study provides a better understanding of the process control in FPCB assembly.</jats:p>
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<jats:title content-type="abstract-subheading">Originality/value</jats:title>
<jats:p>This study provides fundamental guidelines and references for the thermal coupling modelling to address reliability issues in FPCB design. It also increases the understanding of FPCB and BGA joint issues to achieve high reliability in microelectronic design.</jats:p>
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