Acoustic resonator filter with reduced electromagnetic influence due to die substrate thickness

A method for batch processing acoustic resonators, comprising:

• forming a plurality of depressions in a top surface of a substrate;
• depositing a sacrificial material in each of said depressions;
• depositing a first electrode on an upper surface of said sacrificial material in each of said depressions;
• depositing a layer of piezoelectric material on said first electrode;
• depositing a second electrode on said layer of piezoelectric material;
• and polishing a bottom surface of said substrate to reduce the thickness of said substrate.

An acoustic filter, comprising:

• a die substrate having a thickness of less than 19 mils;
• a plurality of acoustic resonators formed on a top surface of the substrate, each acoustic resonator including first and second electrodes and a piezoelectric material disposed in between the first and second electrodes;
• a plurality of interconnects providing electrical connections to said plurality of acoustic resonators;
• and
• a package having a die cavity formed therein, said die substrate being mounted in said die cavity such that a primary current flowing along an upper surface of said die substrate creates a primary current magnetic field, and an image current flowing along a ground plane beneath said die substrate creates an image current magnetic field, said primary current magnetic field and said image current magnetic field having opposite polarities.