Dielectric constant measurement of zeolite powders by time-domain reflectometry

Low-dielectric-constant (low-k) insulator materials are desired for future integrated circuits (IC) to lower both the crosstalk between wires and power consumption. Previous work in our group has demonstrated that pure silica zeolites (PSZs) are the best candidates for ultra low-k materials. Although there are many different types of zeolite framework structures, only a few (e.g., MFI and MEL) have been investigated because measurement of the dielectric constant requires the preparation of a high quality thin film. The development of a simple measurement method for powdered zeolite samples is essential to accelerate the screening process for zeolites. In this paper, time-domain reflectometry (TDR) coupled with the use of a transmission line is introduced for the first time for measuring low-k powdered materials. The technique can quickly measure the dielectric constants of powdered samples over a large frequency range using less than 0.5 g of sample with high reliability and accuracy. Successful measurements on quartz and high-k materials (e.g., HfO_2) indicate that this method can be applied to powdered samples in general.