JPH0230922Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electrode structure of a tuning fork type crystal resonator.

Conventionally, the electrode formation method of a tuning fork crystal resonator includes:
There are two methods: one is to perform vapor deposition using a metal mask, and the other is to use photo etching. The present invention is an electrode structure for improving the reliability of electrode formation of a tuning fork crystal resonator in a method of forming electrodes by vapor deposition using a metal mask.

In explaining the present invention, the names of each part of a typical tuning fork type crystal vibrating piece are defined with reference to FIGS. 1, 2, and 3. FIG. 1 is a perspective view showing the shape of a tuning fork-type crystal vibrating piece, in which a is a resonating part, b is a base, c is a main surface, d is an inner surface, and e is an outer surface.

FIG. 2 is a perspective view of a tuning fork-type crystal vibrating piece in which a metal mask for forming electrodes is placed. 3 is a cross-sectional view taken along the line α-α' in FIG. 2, and FIG. 4 is a cross-sectional view taken along the line β-β' in FIG. R is a vapor deposition source, and the tuning fork-shaped crystal vibrating piece 1 with a metal mask 2 set thereon rotates in the direction of the arrow above the vapor deposition source R.

When forming electrodes by vapor deposition using a metal mask, holes (hereinafter referred to as holes) must be made in the metal mask to match the electrode structure to be formed. Since the edge part is quite large (area), the parts other than the edge (hereinafter referred to as the frame) have many thin parts, and the reinforcing part A (hereinafter referred to as the bridge part) which is not necessary for electrode formation is required. There is. Due to the need for strength, the thickness of the bridge portion A is limited to about 0.1 mm, which is insufficient for reinforcement to make it even thinner.
When an electrode is formed by vapor deposition using a metal mask 2 having a bridge portion A, the bridge portion A blocks the vapor deposition on the outer surface of the tuning fork-shaped crystal vibrating piece during vapor deposition, resulting in an insufficient vapor deposition state. become. FIG. 3 is a sectional view taken along the line α-α' in which the bridge portion A is located. Electrodes are formed on the tuning fork type crystal vibrating piece 1 point-symmetrically with respect to the center point Vapor deposition is performed only from one location B.

FIG. 4 is a sectional view taken along the line β-β', and vapor deposition is performed on the outer surface e from two locations, upper and lower.

FIG. 6 is a perspective view showing the electrode structure deposited using the metal mask of FIG. 2. In the figure, F is a portion that is shielded by the bridge portion A and is not subjected to vapor deposition. In FIG. 6, 3 is an outer surface electrode, 4 is a main surface electrode, 5 is a connection electrode, and 6 is an inner surface electrode. 7th
The figure is a schematic diagram for explaining the connection of electrodes. One of the main surface electrodes 4 is connected to the opposite main surface via the outer surface, the other is connected to the inner surface electrode 6, and the other is connected to the outer surface electrode via the connection electrode 5.
F in the figure corresponds to F in FIG. Although only one location is shown in FIG. 6, there are two locations because the shape is symmetrical. Next, the reason why the electrical conduction of the outer surface electrode is unstable will be explained below.

A tuning fork type crystal vibrating piece in which electrodes are formed by vapor deposition using a metal mask is usually created by mechanical polishing. The surface roughness of a tuning fork-shaped crystal vibrating piece is different between the main surface and the side surfaces, and even after surface treatment using etching, the roughness of the main surface is 0.2 μm and the roughness of the side surfaces is 2 to 3 μm. .

On the other hand, the film thickness of vapor deposition is 1000 to 3000 Å (Japanese Patent Application Laid-Open No.
10692), so the main surface has a roughness of about the same level as the surface roughness.
On the sides, the roughness is about 1/10 of the surface roughness. Furthermore, the film thickness on the side surfaces is thinner than on the main surface (because there is a limit to the size of the groove).

Due to the above-mentioned reason, a conduction failure occurs near the bridge portion A.

An object of the present invention is to obtain an electrode structure that does not cause poor conduction of side electrodes even when a metal mask having a bridge portion is used.

FIG. 5 is a perspective view of a tuning fork type crystal vibrating piece having an electrode structure according to the present invention. The auxiliary electrode E part is an electrode formed on the main surface, and is formed in the vicinity of the F part where it is shielded by the bridge part A and electrical continuity becomes unstable in the prior art.

FIG. 8 is a schematic diagram of the F section and its vicinity, in which the electrode structure of the present invention is developed. As can be seen from the figure, even if section F crosses the outer surface electrode, electrical continuity is established by the auxiliary electrode E section formed on the main surface, eliminating defects caused by disconnection of the outer surface electrode in the prior art. Can be done.

As stated above, the gist of the present invention is to provide an electrode structure in which conduction defects do not occur on the outer surface electrodes because they are shielded by a metal mask when forming electrodes on a tuning fork-shaped crystal vibrating piece by vapor deposition. The portion where the outer surface electrode is shielded can now be electrically connected to the auxiliary electrode portion formed on the main surface, improving the reliability of electrode formation.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the shape of a tuning fork type crystal vibrating piece. Figure 2 is a perspective view of a tuning fork-shaped crystal vibrating piece with a metal mask for electrode formation,
Figure 4 is a cross-sectional view along β-β' in Figure 2, Figure 5 is a perspective view of an embodiment of the present invention, and Figure 6 is a vapor deposition using the metal mask shown in Figure 2. FIG. 7 is a schematic diagram for explaining the electrode structure, and FIG. 8 is a schematic diagram of the F section and the vicinity of the developed electrode structure of the present invention. a...resonant part, b...base, c...principal surface, d...
...Inner surface, e...Outer surface, A...Bridge part, B
...Mad, E...Auxiliary electrode, F...Bridge part A
The portion shielded by R... evaporation source, A1...
Tuning fork type crystal vibrating piece, 2...metal mask.

Claims (1)

[Scope of utility model registration request] In the electrode structure of a tuning fork type crystal resonator, in which electrodes are formed by vapor deposition using a metal mask having a reinforcing part, the main surface electrode on the main surface of the tuning fork type crystal vibrating piece and the outer surface electrode on the outer surface are used. A connection electrode to be connected is located at the base of the tuning fork-shaped crystal vibrating piece, and the outer surface electrode is located near the ridgeline on the opposite main surface corresponding to the position where the outer surface electrode is blocked from vapor deposition by the reinforcing portion of the metal mask. An electrode structure of a tuning fork type crystal resonator, characterized in that an auxiliary electrode is formed to be connected to.