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Journal of ELECTRONIC MATERIALS, Vol. 42, No. 9, 2013
DOI: 10.1007/s11664-013-2665-1
2013 TMS
Cyanate Ester-Based Encapsulation Material for High-Temperature Applications
VIVEK CHIDAMBARAM,1,3 ERIC PHUA JIAN RONG,2 GAN CHEE LIP,2 and RHEE MIN WOO DANIEL1
1.Institute of Microelectronics, A*STAR (Agency for Science, Technology and Research), 11 Science Park Road, Science Park II, Singapore 117685, Singapore. 2.School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore. 3.e-mail: nachiappanvc @ime.a-star.edu.sg
Cyanate ester resin-based composite materials have been proposed as potential encapsulants for high-temperature applications. The objective of this study is to develop a cyanate ester-based encapsulant, which can also serve as a ip-chip underll as well as for traditional encapsulation. Two different materials, quartz and alumina llers, have been studied. The impact of shapes and sizes of the llers on the overall thermomechanical properties has been investigated. The adhesion strengths of the materials to the ceramic substrate, Kovar lid, and silicon die have also been characterized. The modulus of the resin and the shape of the llers play a pivotal role in minimizing thermal stress, generated by coefcient of thermal expansion mismatches. Smaller ller particles were found to have better adhesion to the cyanate ester resin. The high-temperature performance of the cyanate ester-based encapsulants was evaluated by thermal aging at 300C for up to 500 h.
Key words: Encapsulant, underll, potting, resin, ller, outgassing
INTRODUCTION
With dwindling oil reserves around the world, oil exploration has moved to greater depths, which is considered an ultra high-pressure (i.e.,>20,000 psi) and high-temperature (i.e., >200C) environment.
However, the realization of fully functional high-pressure high-temperature (HPHT) wells is possible only when microelectronics packaging and interconnections in well logging equipment can survive such high temperatures. While many suitable microelectronics substrate and interconnection materials are available, there are very few encapsulation materials that can operate at 300C.1 Most commercially available encapsulation materials are based on epoxy, polyimide or silicone and cannot function above about 250C.2 The primary objective of this work is to develop a cyanate ester-based encapsulant material that can also serve as an underll at temperatures above 250C.3
Cyanate esters possess several key material properties which make them suitable as high-temperature encapsulant and underll materials. Their thermal stability is adequate to meet the lid sealing process temperature. The stress-releasing characteristics of...