<title>Measuring thermal conductivity and diffusivity by holographic interferometry</title>

Abstract

Knowledge of the thermal conductivity and the thermal diffusivity are the two most important properties for thermal management in microelectronics design. However, it is difficult to measure the thermal conductivity of ordinary bulk materials accurately, especially of materials that have extremely high values such as copper (4 W/cm.K) and diamond (10 to 25 W/cm.K). In this paper, we proposed and demonstrated three methods for measuring the thermal conductivity of bulk materials based on the nondestructive testing technique in holographic interferometry. Their efficacy for measuring high thermal conductivity values of diamond materials is analyzed. We have obtained values of thermal conductivity for aluminum alloy, copper alloy and pure copper, and molybdenum using these methods. The result from one of these methods shows that it is feasible to achieve such measurements for diamond and diamond-like materials. However, to determine the thermal conductivity of diamond materials the method requires that the thermal diffusivity of the sample must be first measured under high thermal excitation. It is also necessary to capture the dynamic thermal process within a fraction of a second.