Transient Electrothermal Analysis Of Interconnects Based On A Transmission Line Network

Due to the shrinking of VLSI feature size and the increasing of the denisty, the interconnect plays a more and more vital role in the performance of the circuit. Electrostatic discharge (ESD) and Joule heating can make the interconnect temperature and resistance increase, and the reliability decrease. Furthermore, thermal problem may lead to degradation of the circuit performance and even damage of the device. The electrothermal coupling effect brings positive feedback and exacerbates this phenomenon. Hence, accurate estimation of the electrothermal response of interconnect becomes one of the critical issues of IC design.An electrothermal coupling model based on a transmission line network is proposed in this paper and used to analyze the performance of the interconnect. First, we take a typical interconnect system as example, expand the concept of thermal resistance and capacitance, and establish a thermal transmission line network model. Then, moment matching is used to reduce the order and obtain the analytical expression of transient interconnect temperature response. Second, in order to get more accurate simulation of the electrothermal coupling effect, inverse fast Fourier transform (IFFT) and iteration are adopted based on the accurate transmission line model. The method is used to investigate the temperature increase and interconnect performance under ESD pulse and Joule heating. Third, from the electrothermal coupling analysis, it can be seen that this positive feedback effect will lead to significant increase of the temperature, decrease of the circuit performance and damage to device.This work has discussed the transient electrothermal coupling effect of interconnect. Numerical results prove that the method is both accurate and efficient, and is suitable to make reliability analysis of interconnect, and make design guide lines of circuit.