Constructal design for the layout of multi-chip module based on thermal-flow-stress coupling calculation

Abstract

The thermal-flow-stress coupling model of multi-chip module with uniform heat generation under natural convection condition is established. Taking the chip aspect ratio and edge distance as design variables, a comprehensive performance indicator considering the maximum temperature, maximum thermal stress and maximum deformation is constructed to optimize the layout of chips with the constraints of the total occupied areas of printed circuit board and chips according to constructal theory. The results show that the comprehensive performance indicator decreases monotonically with the increase of the chip aspect ratio under the constraints of equal spacing, hence the chips should be designed as thin as possible according to the design requirements. Releasing the constraint of equal spacing, the comprehensive performance indicator increases monotonically with the increase of the edge distance when the chip aspect ratio is constant; the comprehensive performance indicator first decreases and then increases with the increase of chip aspect ratio when the edge distance is constant. The comprehensive performance indicator of the multi-chip module can be reduced by 0.65, the maximum temperature, the maximum thermal stress and the maximum deformation can be reduced by 6.28%, 9.44% and 9.66%, respectively. The methods and results herein could provide theoretical guidance for the thermal design of layout of multi-chip module.