In the present study, a steady-state inverse heat conduction problem is solved by using the conjugate gradient method to estimate the two-dimensional thermal resistance distribution of die-attach materials. The thermal performance of such interface materials is crucial for reliability issues in microelectronics. The spatial distribution of the thermal resistance is obtained from temperature measurements on the upper face of a semiconductor chip. Numerical experiments are performed by simulating infrared thermography measurements. The heat source configuration on the semiconductor chip and the measurement errors are investigated. Finally, the inverse algorithm is improved to decrease the computation time of the identification and to determine the refinement level of the searched distribution.