Package structure of micro speaker and method for forming the same

A method for forming a package structure of a micro speaker, comprising:

• forming an etch stop layer over a substrate, wherein the etch stop layer is made of a metal material;
• forming a dielectric layer over the etch stop layer and the substrate;
• forming a coil structure on the dielectric layer;
• forming a diaphragm on the coil structure so that the coil structure is buried in the diaphragm;
• forming a hollow chamber in the substrate by performing an etching process on a bottom surface of the substrate, wherein the coil structure is isolated from the hollow chamber by the etch stop layer after the etching process;
• attaching a carrier board to the bottom surface of the substrate, wherein a first permanent magnetic element is mounted on the carrier board and positioned in the hollow chamber;
• and
• mounting a package lid on the carrier board, wherein the package lid is wrapped around the substrate and the diaphragm, and has a lid opening that exposes a portion of the diaphragm.