Synthesis and thermal analysis of aluminium nitride filled epoxy composites and its effective application as thermal interface material for LED applications

The improvement of heat conduction in any electronic devices has become a predominant issue in which effective heat dissipation is crucial to enhance the performance of packaged devices. This paper elucidates the application of thermally conductive particles filled composites as thermal interface material for LEDs. Present work aims on reducing the junction temperature and thermal resistance of the device under test with heavily filled ceramic-epoxy composite as the interface material between the device and metal substrate. Silane treated aluminium nitride (AlN) powder was studied for its feasibility as the filler material. The thermal conductivity values obtained by hot disc method (ISO/DIS 22007-2.2) were 0.66, 0.54 and 0.44 W/mK for 60, 50 and 40 wt% AlN filled epoxy composites respectively which were described well by thermal transient measurement of LEDs. The junction temperature and total thermal resistance of the thermal set up was reduced significantly with increased filler loading. The least junction to ambient thermal resistance (RthJ-A) was achieved for 60 wt% followed by 50 and 40 wt% AlN filled TIM with the values of 24.8, 31.98 and 34.64 K/W respectively. Characteristics of the AlN filled composites for LED applications are discussed extensively in terms of thermogravimetric and thermo-mechanical analysis.