Aluminum Nitride Filled Electronic Encapsulants

With the miniaturization, integrated and power-increased of microelectronicdevices, the importance of heat dissipating on the stability, reliability and furtherminiaturization of microelectronic device becomes more prominent. A packagingmaterial with thermal conductive, electrical insulated, and good applicable isneeded.This paper selected vinyl-terminated silicone oil as the matrix, platinum groupcomplexes as the catalyst. The effects of filler surface treatment, filling ofaluminum nitride （AlN） with mixed particle sizes, and filling of AlN/alumina dualfillers on the performances of encapsulant were investigated. The thermalconductivity, volume resistivity, composition viscosity, mechanical properties,hardness and scanning electron microscope of encapsulant were characterized. Ahighly thermal conductive, electrical insulated, good thermal properties and goodapplicable encapsulant was obtained.The types and dosages of silane coupling agents, and surface treatmentprocesses of fillers on the encapsulant performances were investigated. The resultsshowed that the encapsulant perfomed best when surface treatment agent wasn-octyl triethoxysilane, and its dosages was1wt%of fillers, hydrolysis pH wascontrolled at5.0and surface treatmengt was3.5hours.The filling fractions, filler morphology and different particle size mixtures ofaluminum nitride on the performances of encapsulants were investigated. Theresults showed that the encapsulant perfomed best when the filling fraction washigh, the shape of filler used was irregular, different particle size ratio （1μm:5μm）was controlled at1:3.The alumina particle sizes, AlN/alumina mixed ratios on the performances ofencapsulants were investigated. The results showed that the encapsulant perfomedbest when bigger particle size of alumina is used, and AlN/alumina mixed ratio iscontrolled at2:1. Further, combining the best processes above, we obtain a highlythermal conductive, electrical insulated and good applicable encapsulant. Theperformances of optimal encapsulant prepared are as follows: Thermal conductivity（by steady-state method）, volume resistivity, compound viscosity, tensile strength,elongation at break, shore hardness of the encapsulant were1.40W/mK, 5.7*10¹³ cm,1.0*10⁵mPa s,4.3MPa,25%and71, respectively.Thermal conductivity results obtained by steady state method and HotDiskmethod were compared. The ratios of steady state method to HotDisk method isabout1.0:（1.5¹.7）.