Surface acoustic wave resonator device and method for manufacturing the same, and surface acoustic wave filter

A method for manufacturing a surface acoustic wave resonator device, comprising:

• providing a base substrate;
• forming a first layer on the base substrate;
• performing a patterning process on the first layer to form a through hole exposing the base substrate;
• and
• forming an interdigital electrode structure in the through hole of the first layer, such that the interdigital electrode structure is disposed on the base substrate and at least partially embedded in the first layer;
• wherein the interdigital electrode structure comprises a plurality of interdigital electrodes extending along a first direction and arranged along a second direction, and the interdigital electrode structure has an interdigital electrode central region, and a first interdigital electrode end region and a second interdigital electrode end region which are located at two opposite sides of the interdigital electrode central region in the first direction;
• and
• forming a second layer on a side of the first layer and the interdigital electrode structure away from the base substrate,
• wherein the interdigital electrode structure is surrounded and wrapped by the first layer in a direction parallel to a main surface of the base substrate, and a surface of the interdigital electrode structure at a side away from the base substrate is covered by and in contact with the second layer,
• wherein the first layer and the second layer are two layers with an interface between the first layer and the second layer, the interdigital electrode structure comprises a body structure embedded in the first layer and a protruding structure embedded in the second layer, and a surface of the body structure at a side away from the base substrate and a surface of the first layer away from the base structure are level with each other in the direction parallel to the main surface of the base substrate,
• wherein the interdigital electrode structure comprises a seed layer and an electrode material layer, and in the body structure, the seed layer covers a sidewall of the electrode material layer and laterally sandwiched between the electrode material layer and the first layer, and
• wherein in the protruding structure, a sidewall of the electrode material layer is not covered by the seed layer and is in contact with the second layer.