Bulk acoustic wave resonator and method for manufacturing the same

A method to manufacture a bulk acoustic wave resonator, the method comprising:

• sequentially forming an etching stop layer and a sacrificial layer on a substrate;
• forming a pattern in the sacrificial layer such that a portion of the etching stop layer is exposed by the pattern;
• forming an etching stop material on the portion of the etching stop layer exposed by the pattern and the sacrificial layer, so as to fill the pattern;
• planarizing the etching stop material;
• forming a resonating part on the sacrificial layer and a portion of the etching stop material remaining on the pattern after the planarizing;
• and
• forming an air cavity by removing a portion of the sacrificial layer disposed on an inside of the portion of the etching stop material remaining on the pattern.