Surface Modification of Silicon Carbide Nanopartilces by Electroless Plating and Its Application in Isotropic Conductive Adhesive

Nan Wang
Department of Microtechnology and Nanoscience (MC2),
Chalmers University of Technology
Gothenburg, Sweden
Venue: Fasrummet A820

Date: June 12  10 am


 
Abstract
This thesis focuses on the electroless plating process of silicon carbide nanoparticles (SiC NPs) and its application in isotropic conductive adhesive (ICA).  Development of thermal conductivity materials with high thermal conductivity and excellent reliability has already been identified by the microsystems industry as one of the major bottlenecks hindering further integration at packaging level. The development of today’s microelectronic systems has more and more functionality and complexity while the heat produced by microelectronic components is becoming more and more difficult to be dissipated. Therefore, how to quickly transfer heat becomes the major factor to determine the quality of the material. In this thesis, a novel nano-enhanced high thermal conductive adhesive has been developed and characterized. The composition is based on a high temperature conductive epoxy matrix. An efficient heat transfer is achieved through adding silver coated silicon carbide nanoparticles into the material. This special nanoparticle could increase thermal conductivity of the entire system (as compared without nanoparticles adding) while having little effect on the electrical performance. Two different electroless plating methods, the seed-mediated growth method and the autocatalytic method, were developed to synthesize this nanoparticle. Transmission Electron Microscope (TEM) results indicate that those nanoparticles produced by autocatalytic method have a consistent silver layer and no independent silver nanoparticles exists in the final products.
Thermal conductivity test was performed after adding those silver coated silicon carbide nanoparticles produced by the second method. The results show that no obvious changes of thermal conductivity was observed when the ratio of nanoparticles increased from 0 to 1%, and the value is about 4.0w/(m*K) while a significant improvement of thermal conductivity was tested when the percentage of nanoparticles reached to 2% and the value of thermal conductivity is 6.3 w/(m*K). It increases about 60% compared to the case without nanoparticles adding. Also, the electrical properties and reliability of the material were studied in this work. The bulk resistivity results showed that a small amount of nanoparticles adding had little effect on the electrical performance of the entire system. From the viscosity test results, the viscosity increased to some extent with nanoparticles adding. But it can be adjusted by increasing the amount of diluent agent.
Keywords: isotropic conductive adhesive (ICA), electroless plating, silicon carbide, silver coating, nanoparticles, thermal conductivity.

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