Method of manufacturing a piezoelectric vibrator
When a base substrate where through electrodes are formed is anodically bonded to a lid substrate that includes a bonding film formed on the entire lower surface thereof, a method of manufacturing a piezoelectric vibrator includes a superimposing process for superimposing the lid substrate on the base substrate so that a piezoelectric vibrating reed is received in a cavity, after bonding the piezoelectric vibrating reed to the upper surface of the base substrate; a setting process for placing a dummy member, which is made of a material in which ions can be transferred at a bonding temperature, on an electrode plate, and placing the superimposed substrates on the dummy member so that the base substrate faces the dummy member; and an applying process for applying a bonding voltage between the electrode plate and the bonding film after heating the dummy member and the substrates up to the bonding temperature.
1. A method for producing piezoelectric vibrators, comprising:
(a) defining a plurality of first substrates on a first wafer and a plurality of second substrates on a second wafer;
(b) forming a pair of penetration electrodes through respective at least some of the first substrates on the first wafer;
(c) layering the first and second wafers such that at least some of the first substrates substantially coincide respectively with at least some of the corresponding second substrates, with a bonding film sandwiched between the first and second substrates in respective pairs of at least some of coinciding first and second substrates, wherein a piezoelectric vibrating strip is secured in respective pairs of the at least some of coinciding first and second substrates;
(d) placing, on a base plate, the first wafer layered with the second wafer, with an intermediate plate placed between the base plate and the first wafer, wherein the intermediate plate is made of a material in which inner ions are movable at a bonding temperature;
(e) applying, at the bonding temperature, a bonding voltage across the base plate and respective at least some of the bonding films to anodically bond the first and second substrates of the at least some of the respective pairs of the coinciding first and second substrates.
2. The method according to claim 1 , wherein the intermediate plate is made of a material having a thermal expansion coefficient substantially equal to that of the first wafer.