Film bulk acoustic wave resonator, film bulk acoustic wave resonator filter and method of manufacturing film bulk acoustic wave resonator

摘要

The present invention provides a film bulk acoustic wave resonator (FBAR) filter that can keep the Q factor high. The FBAR filter comprises a first FBAR with a first resonant frequency and a second FBAR with a second resonant frequency, formed on a same substrate. The FBAR filter has such a structure that a first underlayer is formed between the substrate and a first bottom electrode layer and a second underlayer is formed between the substrate and a second bottom electrode layer, the first underlayer thickness being different from the second underlayer thickness.