Piezoelectric resonator unit and manufacturing method for the same

A piezoelectric resonator unit, comprising:

• a ceramic substrate having a first main surface and a second main surface opposed to the first main surface;
• a via conductor filling a through hole penetrating the ceramic substrate from the first main surface to the second main surface;
• a connection electrode connected to the via conductor on the first main surface;
• a sealing frame having a frame shape on the first main surface;
• a piezoelectric resonator electrically connected to the connection electrode;
• and
• a lid member bonded to the first main surface of the ceramic substrate so that the piezoelectric resonator is sealed in a space between the ceramic substrate and the lid member,
• wherein the connection electrode and the sealing frame each have a multilayer structure including a lowermost layer and an uppermost layer,
• a first difference between a maximum value and a minimum value of a height from the first main surface of the ceramic substrate to an upper surface of the lowermost layer of the connection electrode is less than 1 μm,
• a second difference between the maximum value of the height from the first main surface of the ceramic substrate to the upper surface of the lowermost layer of the connection electrode and a maximum value of a height from the first main surface of the ceramic substrate to an upper surface of the lowermost layer of the sealing frame is less than 1 μm, and
• a flatness of the uppermost layer of the connection electrode and the uppermost layer of the sealing frame is 5 μm or less.