Influence of thermal contact resistance on thermal impedance of microelectronic structures

摘要

The thermal impedance Z_(th)(jω) has been calculated numerically for a silicon chip glued on a ceramic substrate. The non perfect thermal contact is taken into account by modelling the chip-substrate interface as a thermal contact resistance r_c. If Z_(th) is represented as a Nyquist plot, mainly two circular arcs are observed. The high frequency arc is found to be almost independent from r_c, whereas the low frequency part is largely influenced by r_c. The thermal resistance R_(th) = Z_(th)(jω = 0) increases linearly with r_c, as known from the literature. Additionally, our simulations have shown that similar conclusions can be drawn for the real and imaginary part of Z_(th) at a fixed frequency ω ≠ 0.