Highly reliable embedded thin film resistors in Cu/PI MCM-Ds for aerospace applications

This paper describes the process evaluation and reliability assessment of TaN_0.1 and W/SiO_x thin film resistors and the demonstration of their integration into a Boeing product. These resistors were recently developed for use in Cu/PI MCM-Ds. The TaN_0.1 resistors, unlike the traditional Ta₂ N thin film resistors, do not require the traditional high temperature stabilization treatments. With a resistivity of 0.02×10^-2 Ω-cm (20 Ω/square at a thickness of 1000 Å), they have a near zero thermal coefficient of resistance (TCR), are stable during repeated exposures to polyimide cure temperatures (250-350°C), and demonstrate high reliability in both thermal shock (-55°C to +125°C) and long term high temperature stability tests (125°C, >1000 hours). The W/SiO_x resistors, while being both reproducible and stable, have a resistivity in the range of 0.2-1.5×10^-2 Ω-cm (200-1500 Ω/square at a thickness of 1000 Å) while maintaining a very low TCR (near 0 ppm/°C). The material´s high resistivity allows thicker resistors to be fabricated, therefore, improving the power handling capability. In addition, excellent results from high temperature stability and thermal shock testing demonstrate the high reliability performance of the W/SiO_x material system