Piezoelectric vibrator manufacturing method, piezoelectric vibrator, oscillator, electronic device, and radio-controlled timepiece

A method for manufacturing a piezoelectric vibrator comprising:

• a package in which a first substrate and a second substrate are superimposed so as to form a cavity therebetween;
• outer electrodes which are formed on an outer surface of the first substrate;
• inner electrodes which are formed on the first substrate so as to be accommodated in the cavity;
• penetration electrodes which are formed so as to penetrate through the first substrate so that the outer electrodes and the inner electrodes are electrically connected;
• and
• a piezoelectric vibrating reed which is sealed in the cavity and electrically connected to the inner electrodes at the inner side of the cavity, the method comprising:
• a bonding film forming step of forming a bonding film on at least one of the first substrate and the second substrate using a low-melting-point glass so as to bond the two substrates;
• a mounting step of electrically connecting the piezoelectric vibrating reed to the inner electrodes formed on the first substrate;
• a loading step of loading the first substrate and the second substrate in a vacuum chamber of which the inner pressure can be controlled after the bonding film forming step and the mounting step are performed;
• a heating step of heating the bonding film after the bonding film forming step and the mounting step are performed;
• a depressurization step of depressurizing the inside of the vacuum chamber after the loading step is performed;
• and
• a bonding step of superimposing the first substrate and the second substrate onto each other at the inner side of the vacuum chamber with the bonding film disposed therebetween while heating the bonding film to a predetermined bonding temperature to thereby bond the two substrates by the bonding film after the heating step and the depressurizing step are performed,
• wherein in the heating step, the bonding film is heated to a temperature higher than the bonding temperature.