A Characterization Method for Viscoelastic Bulk Modulus of Molding Compounds

Conference paper (2008)

Authors

MK Saraswat Computational Design and Mechanics - Mechanical, Maritime and Materials Engineering
K.M.B. Jansen Computational Design and Mechanics - Mechanical, Maritime and Materials Engineering
MD Patel Computational Design and Mechanics - Mechanical, Maritime and Materials Engineering
L.J. Ernst Computational Design and Mechanics - Mechanical, Maritime and Materials Engineering
C Bohm External organisation
A Kessler External organisation
H Preu External organisation
M Stecher External organisation
Research Group
Computational Design and Mechanics (Mechanical, Maritime and Materials Engineering) (TU Delft)
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Published Date

2008

Language

Undefined/Unknown

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Faculty

Mechanical, Maritime and Materials Engineering

Department

Precision and Microsystems Engineering

Research Group

Computational Design and Mechanics

Abstract

Reliability calculations of the microelectronic packages require cure dependent viscoelastic constitutive relationship for the packaging polymers in order to predict residual stress and strain fields in the final product. The residual stresses can result in the product failure due to warpage, interfacial delamination, thermal fatigue etc. The previous work in the same group (Ernst et al. 2006, 2003) towards complete viscoelastic model development was done using "approximate fully cure dependent" model in order to predict warpage of the QFN package. The relaxation shear modulus was accurately established but due to measurement limitation only estimated values of bulk modulus could be used. In the present work, a high pressure dilatometer (Gnomix PVT apparatus) was used to establish the time, temperature and pressure dependence of bulk modulus. The bulk modulus shows negligible time dependence which suggests that bulk modulus is not a viscoelastic but merely a temperature dependent linear elastic parameter. A material model for time, temperature and pressure dependency of the bulk Modulus is developed.