| abstract |
Disclosed is a radio frequency, RF, filter that vertically integrates an acoustic wave filter with an integrated passive device, IPD, filter. The acoustic wave filter provides selectivity at fundamental frequency band while the IPD filter provides rejection at harmonic frequency bands. The acoustic wave filter comprises contact areas (415) and on top a passivation layer (420). The IPD filter is formed on top of the passivation layer (420) with Si3N4 MIM capacitors in its lower metal layers (512, 522) and inductors in its upper metal layers (530,540). Metal layers are separated and covered by polyimide insulating layers (525,535,545). External contacts (555,550) are realized on top of the IPD layers. |