Piezoelectric element, manufacturing method thereof, and mounting apparatus of piezoelectric resonators

A method of manufacturing a piezoelectric element having a lead terminal for electrically connecting an electrode formed on the surface of a piezoelectric piece to an external electrical circuit, said piezoelectric element being sealed in a case, comprising the steps of:

• arranging at least one mask in close contact onto a plurality of said piezoelectric resonators arranged at predetermined positions so as to expose a connection surface of an electrode associated with each piezoelectric resonator;
• exposing said connection surface to an excited active species of a discharge gas generated by causing plasma discharge in a predetermined discharge gas at approximately atmospheric pressure to surface treat said connection surface;
• and
• connecting said lead terminal to said connection surface while said lead terminal and said connection surface are exposed to said active species, wherein said at least one mask is formed of a ferromagnetic material and are brought into close contact with said piezoelectric resonators by magnetic attraction between said at least one mask and a base plate having said plurality of piezoelectric resonators placed thereon and being positioned between said at least one mask and said base plate.