Quartz crystal unit and method of manufacturing the same

A method of manufacturing a quartz crystal unit, the method comprising:

• preparing a first substrate for forming a plurality of quartz crystal resonators, the first substrate being made of a quartz crystal, each of the plurality of quartz crystal resonators including a quartz crystal blank on which a pair of excitation electrodes are formed on opposing surfaces thereof, a frame body that surrounds an outer periphery of the quartz crystal blank, and at least one coupling member that couples the quartz crystal blank to the frame body;
• preparing a second substrate for forming a plurality of package members;
• joining the first substrate to the second substrate such that the package member is joined to an entire periphery of the frame body on at least one side of the pair of excitation electrodes;
• forming a recess in a junction region of at least one of the frame body and the package member, with the junction region being where the frame body is joined to the package member;
• and
• forming an extension electrode that is electrically connected to one of the pair of excitation electrodes, wherein the extension electrode is formed in the recess such that the extension electrode has a thickness that does not exceed a depth of the recess.