Basic Properties of an LC Filter Using a Thin-Film Inductor

This paper discusses the application of thin-film inductors to thin-film-based LC filters. We fabricated a monolithic thin-film LC filter by using rf sputtering and dry etching techniques. The filter consists of thin-film inductors and thin-film capacitors fabricated on a common substrate. This filter was designed as a second-order low-pass filter having Chebyshev characteristics, with a cut-off frequency of 50 MHz. We developed a technique for measuring this two-port device at high frequencies, and then measured the frequency characteristics. Here we discuss the merits of thin-film LC filters using soft magnetic thin films.