# Numerical analysis of thermal stresses induced during VFM encapsulant curing

Tilford, T., Sinclair, K.I., Goussetis, G., Bailey, C., Desmulliez, M.P.Y., Parrott, A.K. and Sangster, A.J.
(2008)
*Numerical analysis of thermal stresses induced during VFM encapsulant curing.*
In: 31st International Spring Seminar on Electronics Technology, 2008. ISSE '08.
Institute of Electrical and Electronics Engineers, Inc., Piscataway, NJ, USA, pp. 348-353.
ISBN 978-1-4244-3972-0
(doi:10.1109/ISSE.2008.5276666)

## Abstract

Encapsulant curing using a Variable Frequency Microwave (VFM) system is analysed numerically. Thermosetting polymer encapsulant materials require an input of heat energy to initiate the cure process. In this article, the heating is considered to be performed by a novel microwave system, able to perform the curing process more rapidly than conventional techniques. Thermal stresses are induced when packages containing materials with differing coefficients of thermal expansion are heated, and cure stresses are induced as thermosetting polymer materials shrink during the cure process. These stresses are developed during processing and remain as residual stresses within the component after the manufacturing process is complete. As residual stresses will directly affect the reliability of the device, it is necessary to assess their magnitude and the effect on package reliability. A coupled multiphysics model has been developed to numercially analyse the microwave curing process. In order to obtain a usefully accurate model of this process, a holistic approach has been taken, in which the process is not considered to be a sequence of discrete steps, but as a complex coupled system. An overview of the implemented numerical model is presented, with particular focus paid to analysis of induced thermal stresses. Results showing distribution of stresses within an idealised microelectronics package are presented and discussed.

Item Type: | Conference Proceedings |
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Title of Proceedings: | 31st International Spring Seminar on Electronics Technology, 2008. ISSE '08 |

Additional Information: | [1] Paper forms part of the 31st International Spring Seminar on Electronics Technology, ISSE 2008 - Reliability and Life-time Prediction, held 7-11 May 2008 in Budapest, Hungary. |

Uncontrolled Keywords: | Variable Frequency Microwave (VFM) system, cure process, thermosetting polymer, encapsulant, thermal stresses, numerical analysis |

Subjects: | T Technology > TK Electrical engineering. Electronics Nuclear engineering Q Science > QA Mathematics |

Pre-2014 Departments: | School of Computing & Mathematical Sciences School of Computing & Mathematical Sciences > Centre for Numerical Modelling & Process Analysis School of Computing & Mathematical Sciences > Centre for Numerical Modelling & Process Analysis > Computational Mechanics & Reliability Group School of Computing & Mathematical Sciences > Centre for Numerical Modelling & Process Analysis > Computational Science & Engineering Group School of Computing & Mathematical Sciences > Computer & Computational Science Research Group School of Computing & Mathematical Sciences > Department of Computer Science School of Computing & Mathematical Sciences > Department of Computer Systems Technology School of Computing & Mathematical Sciences > Department of Mathematical Sciences |

Related URLs: | |

Last Modified: | 14 Oct 2016 09:03 |

URI: | http://gala.gre.ac.uk/id/eprint/1223 |

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