Surface acoustic wave resonance device and method for forming same, filter device, and radio frequency front end device

A surface acoustic wave resonance device, comprising:

• a piezoelectric substrate;
• an electrode layer disposed on the piezoelectric substrate along a first direction, wherein the electrode layer comprises an interdigital transducing device, and the interdigital transducing device comprises a first busbar portion, a second busbar portion and an interdigital portion disposed between the first busbar portion and the second busbar portion along a second direction;
• a first load layer disposed above the interdigital portion along the first direction and close to the first busbar portion along the second direction;
• a first dielectric layer disposed above the electrode layer along the first direction and covering the first load layer;
• and
• a second load layer disposed on the first dielectric layer along the first direction and close to the second busbar portion along the second direction;
• wherein a first region is disposed between the first load layer and the second load layer along the second direction, a second region is disposed between the first busbar portion and the first load layer along the second direction, a third region is disposed between the second busbar portion and the second load layer along the second direction, a fourth region is disposed between the first region and the second region along the second direction, and a fifth region is disposed between the first region and the third region along the second direction, wherein the first load layer is disposed in the fourth region, and the second load layer is disposed in the fifth region, wherein a first wave velocity of an acoustic wave in the first region is greater than a second wave velocity of the acoustic wave in the fourth region, and is also greater than a third wave velocity of the acoustic wave in the fifth region, and the second wave velocity is different from the third wave velocity.

A method for forming a surface acoustic wave resonance device, comprising:

• providing a piezoelectric substrate;
• forming an electrode layer on the piezoelectric substrate along a first direction, wherein forming the electrode layer comprises forming an interdigital transducing device, and the interdigital transducing device comprises a first busbar, a plurality of first electrode strips, a second busbar and a plurality of second electrode strips, wherein a first end of each of the plurality of first electrode strips is coupled with the first busbar, a second end of each of the plurality of first electrode strips opposite to the first end along a second direction is close to the second busbar, and a first gap is disposed between the second end and the second busbar, wherein a third end of each of the plurality of second electrode strips is coupled with the second busbar, a fourth end of each of the plurality of second electrode strips opposite to the third end along the second direction is close to the first busbar, and a second gap is disposed between the fourth end and the first busbar;
• forming a first load layer above the fourth end along the first direction and close to the first end and the second gap along the second direction, wherein the first load layer intersects with the plurality of first electrode strips to form a plurality of first overlap portions, and the first end is disposed between the first busbar and the plurality of first overlap portions, wherein the first load layer also intersects with the plurality of second electrode strips to form a plurality of second overlap portions, and the plurality of second overlap portions are close to the second gap;
• forming a first dielectric layer above the electrode layer along the first direction and covering the first load layer;
• and
• forming a second load layer on the first dielectric layer and above the second end along the first direction and close to the third end and the first gap along the second direction, wherein the second load layer intersects with the plurality of first electrode strips to form a plurality of third overlap portions, and the plurality of third overlap portions are close to the first gap, wherein the second load layer also intersects with the plurality of second electrode strips to form a plurality of fourth overlap portions, and the third end is disposed between the second busbar and the plurality of fourth overlap portions.