JPH09270653A - Manufacture of electrode film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep the characteristic and quality of a vibrator by selecting the thickness of an outer circumferential ridge of an opening of front and rear vapor-deposition masks thinner than a plate thickness of the vapor-deposition mask to form the electrode film. SOLUTION: A vibration chip 10 is covered by a front vapor-deposition sub-mask 12 having an opening 11. Then mount parts 16, 17 are formed and the thickness of a side wall of an outer circumferential ridge 15 of the opening 11 of the front vapor-deposition sub-mask 12 is formed thin. Then a cross section 13 of the outer circumferential ridge 15 of the opening 11 of the front vapor- deposition sub-mask 12a is formed by one-side pressing after, e.g. etching so that a tilt angle is nearly 30 deg. toward the center of the opening 11. Thus, in the case of soldering the mount 16 and a support rod, intrusion due to solder is eliminated and the quality is made stable. Moreover, the shift in the frequency of the vibrator is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an electrode film of a vibrating piece made of a piezoelectric material.

[0002]

2. Description of the Related Art A vibrator in which a vibrating piece made of a piezoelectric material is provided with an exciting electrode film is widely used. In this case, the manufacturing method for forming the electrode film of the vibrator often affects its quality and cost. Although an AT-cut crystal oscillator will be taken as an example below, the material (piezoelectric ceramic, crystal) of the oscillator, the vibration mode, and the type of the electrode film are not limited to the examples.

FIG. 3 is an external view of an AT-cut crystal unit. FIG. 4 is a schematic diagram of a vapor deposition device that forms an electrode film on a vibrating piece. FIG. 5 is a top view of FIG. FIG. 6 is a relational development view of a vapor deposition holder set. FIG. 6A is a thin plate-shaped front vapor deposition mask (hereinafter abbreviated as front vapor deposition mask), FIG. 6B is a vibrating piece group, and FIG. A thin plate-shaped vapor deposition holder (hereinafter abbreviated as vapor deposition holder), and FIG. 6D shows a thin plate-shaped back vapor deposition mask (hereinafter abbreviated as back vapor deposition mask). FIG. 7A is a detailed explanatory diagram of the relationship between the resonator element, the front vapor deposition mask, and the electrode film. FIG. 3B is a sectional view taken along line AA of FIG. FIG. 6C is an explanatory diagram of the relationship between the resonator element, the back evaporation mask, and the electrode film. FIG. 8 is an explanatory diagram of the structure of the electrode film of the mount portion.

In FIG. 3, an AT-cut crystal unit 10
0 means that the mount portion of the quartz crystal vibrating piece 101 (hereinafter referred to as a vibrating piece) having the electrode film 102 (the back electrode film is not shown) provided on the surface of the vibrating piece is the stem 10.
It is configured by being connected and fixed to the metal support rods 104 and 105 arranged in No. 3 with solder or the like.

In the example shown in FIG. 4, in a vapor deposition apparatus 200 which is a vacuum chamber having a bell jar 201, a chromium material target (hereinafter abbreviated as chromium) 205 for forming an electrode film of a vibrating element by vapor deposition, a silver material. A target (abbreviated as silver below) 206 is installed. Also,
A plurality of vapor deposition holder sets 210 to 219 (2 in the figure) holding a plurality of vibrating pieces (hereinafter, abbreviated as a vibrating piece group).
(Only 10 and 215 are shown) are provided on the central shaft 209 in an umbrella shape and revolve 208. Vapor deposition holder set 210, 215
Has an angle of α, β, γ, and δ when viewed from the chrome 205, and has inclination angles of approximately 50 °, 40 °, 80 °, and 90 °, respectively. Similarly, α ′, β ′, when viewed from silver 206,
The angles γ ′ and δ ′ are different from the chrome 205 in the central axis 20.
There is an axisymmetric relationship with respect to 9, and they are approximately 50 ° and 40, respectively.
It has inclination angles of °, 80 ° and 90 °. This shows that the electrode film formed by vaporizing the metal from the chromium 205 and the silver 206 and adhering to the vibrating piece has a vapor deposition angle with respect to the height direction. Further, the angles α to δ,
α ′ to δ ′ vary depending on the size of the vapor deposition apparatus, the size of the vapor deposition holder set and the number to be set, and the arrangement of the chromium 205 and the silver 206.

FIG. 5 is a top view of the vapor deposition apparatus 200. The vapor deposition holder sets 210 to 219 are configured so that not only the total of 10 sets can be revolved 208 but also the reversal 207 can be performed. Therefore, evaporation holder set 21
0 to 219, and chromium 205 and silver 20 on necessary parts on the front and back of the vibrating piece group covered with a vapor deposition mask described later.
The evaporated metal of No. 6 is laminated to form an electrode film. In this case, there are vapor deposition angles a to i in the plane direction as seen from the chrome 205, and similarly, although not shown in the diagram as seen from the silver 206, there are similar vapor deposition angles in the plane direction. The vapor deposition angles a to i vary depending on the size of the vapor deposition apparatus, the size of the vapor deposition holder set and the number to be set, and the arrangement of the chromium 205 and the silver 206. In this example, a to i are 30 °, 120 °, and 12 respectively.
0 °, 110 °, 95 °, 85 °, 65 °, 45 °, 3
5 °.

The vapor deposition holder set 210 shown in FIG. 6 is constructed as follows. Width 0.8-2 mm, length 3-8
mm, thickness 0.1 to 0.2 mm, a plurality of vibrating reeds are arranged in a plurality of rows to form a vibrating reed group 220 (FIG. (B)), and a plurality of small holes slightly larger than the outer shape of the vibrating reed are provided in a plurality of rows. A front deposition mask 230 (FIG. (A)) housed in an arrayed deposition holder 210 ′ (FIG. (C)) and having an opening for forming an electrode film smaller than the small holes of the deposition holder 210 ′, and the deposition holder. It is sandwiched by a jig (not shown) with a back evaporation mask 240 (FIG. 2D) having an opening for forming an electrode film smaller than the small holes 210 '. Here, the vibrating piece 220a, which is one of the vibrating piece group 220, is the small hole 210a of the vapor deposition holder 210 ', the front vapor deposition mask 2
The openings 230a of 30 and the openings 240a of the back vapor deposition mask 240 respectively correspond.

In FIG. 7A, a partial mask of the surface vapor deposition mask 230 corresponding to the opening 230a is referred to as a surface vapor deposition submask 230b. The vibrating piece 220a is covered with the front vapor deposition sub-mask 230b so that the opening 230
A chromium material is formed on the base as an electrode film on a and a silver material is formed thereon, and the mount portions 250 and 251 are also formed of the electrode film. 260 indicates the thickness of the electrode film at the peripheral edge of the opening 230a. FIG. 2B shows a cross-sectional view taken along the line AA of FIG.
The minimum inclination angle 252 of the vaporized metal due to the chromium 205 and the silver 206 adhering to 51 is slightly less than about 30 °. That is, FIG.
Since the vapor deposition holder set has a vapor deposition angle as described with reference to FIG. 5, the side wall of the front vapor deposition sub-mask 230b causes a shadow on the peripheral edge of the opening 230a. Similarly, the vibrating piece 220a is formed on the back evaporation sub-mask 240b.
And a silver material is formed on the underlying layer as an electrode film in the opening 240a.
0'and 251 'are also formed of the electrode film. Reference numeral 260 'indicates the thickness of the electrode film around the periphery of the opening 240a. The minimum inclination angle of the evaporated metal by the chromium 205 and the silver 206 attached to the mounts 250 ′ and 251 ′ of the opening 240a is about 30 ° or less. That is, since the vapor deposition holder set has a vapor deposition angle as described with reference to FIGS. 4 to 5, the opening 2 is formed by the sidewall of the back vapor deposition sub-mask 240b.
A shadow will be produced on the periphery of 40a.

As an example of the mount portion, the mount portion 250 of the vibrating piece 220a will be described as shown in FIG. A chromium material 255 and a silver material 256 are laminated thereon by vapor deposition to form an electrode film of the mount section 250. Also,
In order to improve the adhesion of the electrode films 255 and 256 to the vibrating piece 220a, generally, 200 ° C. to 300 ° C. × 1
Support bars 104, 105 after heat treatment for ~ 2 hours
Solder connection 257 is made into a vibrator. (Figure omitted)

[0010]

SUMMARY OF THE INVENTION However, FIGS.
As described with reference to FIG. 8, the peripheral edge 25 of the mount part 250.
The electrode films 3 and 254 are thinner than the central electrode film. Therefore, when the mount portion 250 is solder-connected 257, the thin electrode films on the peripheral edges 253 and 254 are eaten by the solder, resulting in a connection failure.

The thickness of the underlying chromium material electrode film 255 of the mount portion 250 must meet the following conditions.
That is, in order to prevent the above-mentioned solder bite, 10
A thickness of 0 angstrom or more is desirable, and a thickness of 200 angstrom or less is desirable to secure the characteristics of the vibrator. However, in the conventional manufacturing method, the chromium material electrode film 255 on the peripheral edges 253 and 254 of the mount part 250 is a thin electrode film of 100 angstroms or less, and the necessary conditions cannot be satisfied.

Further, the chromium material electrode film 255 and the silver material electrode film 256 produced by the conventional manufacturing method have a problem that the frequency of the vibrator is shifted and the quality is deteriorated.

An object of the present invention is to provide a method of manufacturing an electrode film for maintaining the characteristics and quality of a vibrator.

[0014]

Means for Solving the Problems In a vacuum chamber, a plurality of piezoelectric vibrating pieces are housed in a vapor deposition holder having a plurality of small holes. In the manufacturing method of sandwiching the vibrating piece by stacking a pair of a plurality of vapor deposition masks having a small opening, and forming an electrode film on the front and back of the vibrating piece, the thickness of the outer peripheral edge of the opening of the vapor deposition mask on the front and back. Is set to be thinner than the plate thickness of the vapor deposition mask to form the electrode film.

The electrode film is formed by setting the cross-sectional shape of the outer peripheral edges of the openings of the vapor deposition masks on the front and back sides so that the openings shrink toward the center of the openings. Manufacturing method.

It is characterized in that the electrode film is formed by setting a step so that the cross-sectional shape of the outer peripheral edge of the opening of the front and back evaporation mask becomes thinner toward the center of the opening.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1A is an explanatory view of the relationship between the resonator element and the vapor deposition submask according to the manufacturing method of the present invention.
FIG. 3B is a sectional view taken along line AA of FIG. FIG. 7C is another embodiment according to the present invention shown as a cross-sectional view taken along the line AA of FIG. FIG. 2 is an explanatory diagram of the electrode film of the mount portion according to the manufacturing method of the present invention.

In FIG. 1 (A), the resonator element 10 is covered by a surface vapor deposition submask 12 having an opening 11. The back surface of the vibrating element 10 is covered with a back evaporation sub-mask, but the illustration and description thereof are omitted because they work in the same manner as the conventional example. The mount portions are formed at 16 and 17, and the outer peripheral edge 15 of the opening portion 11 of the surface vapor deposition submask 12 is a portion whose side wall is thin as described later.

In FIG. 1B, a cross section 13 of the outer peripheral edge 15 of the opening 11 of the surface vapor deposition sub-mask 12a according to the present invention.
Is formed by, for example, single-sided pressing after etching so that the inclination angle becomes about 30 ° toward the center of the opening 11.

FIG. 3C shows another embodiment of the present invention,
The step 14 is formed by half etching or the like so that the cross section of the outer peripheral edge 15 of the opening 11 of the front vapor deposition sub-mask 12b is approximately 1/2 of the thickness of the front vapor deposition sub-mask 12b.

According to FIG. 1B of the present invention, since no shadow is generated on the mount parts 16 and 17 by the side wall of the opening 11, the electrode films are uniformly attached to the mount parts 16 and 17.

FIG. 2 is a detailed explanatory view of the mount portion 16 of FIG. 1 (C). Surface deposition sub-mask 12b on the vibrating piece 10
Since the cross section of the outer peripheral edge 15 of the opening 11 has a step 14, compared with the conventional vapor deposition sub-mask 18, even if the vapor deposition angle is about 30 °, the shadow due to the vapor deposition mask is halved and the periphery of the mount 16 is reduced. The thickness of the chromium electrode film 19 including is 10
It can be formed to 0 to 200 angstroms.

[0023]

According to the present invention, when the mount portion 16 and the supporting rod are connected by soldering, the quality is stable without being eaten by the solder.

According to the present invention, the frequency and the yield of the vibrator are improved because the frequency of the vibrator is less shifted, and the cost / performance of the vibrator can be remarkably improved because the shape of the vapor deposition mask is simple. .

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a relationship between a resonator element and a vapor deposition submask according to a manufacturing method of the present invention.

FIG. 2 is an explanatory diagram of an electrode film of a mount portion according to the manufacturing method of the present invention.

FIG. 3 is an external view of a conventional AT-cut crystal unit.

FIG. 4 is a schematic view of a vapor deposition device for forming an electrode film on a conventional resonator element.

5 is a top view of FIG. 4. FIG.

FIG. 6 is a relationship development view of a conventional vapor deposition holder set.

FIG. 7 is a detailed explanatory diagram showing a relationship between a conventional resonator element, a front vapor deposition mask, and an electrode film.

FIG. 8 is an explanatory diagram of a configuration of an electrode film of a conventional mount section.

[Explanation of symbols]

 Reference Signs List 10 vibrating piece 11 opening 12 surface vapor deposition submask 12a surface vapor deposition submask 12b surface vapor deposition submask 13 vapor deposition mask cross section 14 step 15 outer peripheral edge of opening 16, 17 mounting portion 18 vapor deposition submask 19 chromium electrode film 101 quartz crystal vibrating piece 102 electrode film 103 stem 104, 105 Support bar 200 Vapor deposition apparatus 201 Bell jar 205 Chrome 206 Silver 207 Inversion 208 Revolution 209 Center axis 210-219 Vapor deposition holder set 210 'Vapor deposition holder 210a Small hole 220 Vibrating piece group 220a Vibrating piece 230 table Vapor deposition mask 230a Opening 230b Table Vapor deposition sub-mask 240 Back vapor deposition mask 240a Opening 240b Back vapor deposition sub-mask 250, 251 Mounting part 250 ', 251' Mounting part 252 Minimum inclination angle 253 Electrode film peripheral edge 254 The thickness of the electrode film periphery 255 chromium material 256 silver material 257 solder connections 260 and 260 'electrode film

Claims (3)

[Claims] 1. A thin plate-shaped vapor deposition holder having a plurality of small holes, in which a plurality of piezoelectric vibrating pieces are housed in a vacuum chamber.
On the front and back of the thin plate-shaped vapor deposition holder, a pair of a plurality of thin plate-shaped vapor deposition masks having openings smaller than the small holes of the vapor deposition holder are overlapped to sandwich the vibrating piece, and electrode films are provided on the front and back of the vibrating piece. In the manufacturing method for forming an electrode film, the electrode film is formed by setting the thickness of the outer peripheral edges of the openings of the thin plate-shaped vapor deposition masks on the front and back sides to be smaller than the plate thickness of the vapor deposition mask. 2. The electrode film is formed by setting the cross-sectional shape of the outer peripheral edge of the opening of the thin plate-shaped vapor deposition masks on the front and back sides so that the opening shrinks toward the center of the opening. The method for producing an electrode film according to claim 1. 3. An electrode film is formed by setting a step so that the cross-sectional shape of the outer peripheral edge of the opening of the thin plate-shaped vapor deposition masks on the front and back sides becomes thinner toward the center of the opening. Item 2. The method for producing an electrode film according to Item 1.