Thin film resistors and capacitors for advanced packaging

Integrated passive components are important for high frequency hybrid microelectronics. We have fabricated resistors using reactively sputtered TaN/sub x/ (x<0.5) and Ta/sub 2/Si thin films. We report on the resistivity, temperature coefficient of resistance (TCR), microstructure, composition, and thermal stability as a function of deposition conditions. The resistivity can be tuned, for example, by varying the nitrogen concentration. We have also fabricated capacitors with high capacitance density (70 nF/cm/sup 2/) using Ta/sub 2/O/sub 5/ dielectric films. The Ta/sub 2/O/sub 5/ dielectric films were prepared by various methods such as reactively sputtered Ta/sub 2/O/sub 5/, anodization of reactively sputtered TaN,, and anodization of Ta,Si films. We report on the capacitance density, leakage current, breakdown voltage, and dissipation factor up to high frequencies. We also report on the temperature coefficient of capacitance (TCC) and thermal stability of these capacitors during subsequent processing. A variety of analytical techniques were used to characterize the film properties. These anodic Ta/sub 2/O/sub 5/ capacitors have exceptionally low leakage currents (<1 nA/cm/sup 2/ at 10 V), high breakdown fields (>4 MV/rm), and high capacitance densities (70 nF/cm/sup 2/). The ac measurements of the capacitors showed ideal behavior up to 10 MHz Generally, anodic capacitors degrade upon subsequent processing above 200/spl deg/C due to dielectric and electrode metal interaction. By engineering the dielectric and the electrode materials, we have fabricated anodic Ta/sub 2/O/sub 5/ capacitors that are stable up to 350/spl deg/C with excellent capacitor properties. These capacitors are useful as integrated passive components for advanced packaging applications.