JP2728036B2 - Manufacturing method of piezoelectric vibrator - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a piezoelectric vibrator. 2. Description of the Related Art A conventional piezoelectric oscillator is disclosed in Japanese Unexamined Patent Publication No.
No. 204 has a structure as shown in FIG. 9 and includes a piezoelectric vibrator 11 and a piezoelectric vibrator 11.
The semiconductor 12 that electrically oscillates and the metal leads that electrically connect them are formed by resin molding. The case body and plug body of the piezoelectric vibrator 11 used here are plated with solder having a lead content of 40% or less for the main reason of appearance,
In addition, it has been known that a vibrating reed is soldered to a plug body with solder having the above composition, and the plug body is vacuum-pressed into a case using the solder having the above composition as a sealing material. [0003] However, in the above-mentioned prior art, an SMT (Surface Mount Tech) is used.
When used as a (nology) component, there is a basic problem that when mounted on a substrate, the entire component reaches 220 to 260 ° C. and is melted by solder having a composition with a lead content of 40% or less. In addition, characteristic deterioration such as shift of the frequency and the equivalent resistance value of the piezoelectric vibrator has occurred. When this was examined, it was found that gas was released from inside the solder plating due to the high temperature exposed at the time of SMT mounting, and this was due to the effect. Accordingly, the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a piezoelectric vibrator having heat resistance to a high temperature of 260 ° C. or more in SMT mounting. It is to provide a manufacturing method. According to the present invention, there is provided a method for manufacturing a piezoelectric vibrator, wherein a side surface of a plug body and an entire surface of an inner lead are lead-containing by solder plating using a plating solution containing an organic component. Plating with lead-tin solder having a ratio of not less than 90%, heating the solder plated on the inner lead to fix the piezoelectric vibrating reed to the inner lead, and the plug having the piezoelectric vibrating reed fixed to the inner lead. The body and the case are baked in a vacuum atmosphere, and the plug is hermetically press-fitted into the case using a solder plated on a side surface of the plug as a sealing material. FIG. 1A is a perspective view of an example of a piezoelectric oscillator using a piezoelectric vibrator manufactured by the manufacturing method of the present invention, and FIG. 1B is a perspective view of FIG. a) Cross section, FIG.
(A) is an assembly plan view showing another example of the piezoelectric oscillator,
2B is an assembled sectional view of FIG. 2A, FIG. 3 is a sectional view of a piezoelectric vibrator, FIG. 4 is a sectional view of a vibrating piece of the piezoelectric vibrator, and FIG. FIG. 6 is a cross-sectional view of a case body of the piezoelectric vibrator. An embodiment will be described below. First, the piezoelectric vibrating reed 102 on which the electrode film 101 shown in FIG. 4 is formed by vapor deposition or the like is placed on the inner lead 104 side of the plug body shown in FIG.
3 is soldered 106 as shown in FIG. 3, and hermetically pressed into a metal case 105 plated with solder 103 shown in FIG. 6 using the solder 103 shown in FIG. 3 as a sealing material. The solder 103 is a solder having a lead (Pb) content of 90% or more in the solder phase diagram shown in FIG. 7, and has a melting temperature of 260 ° C. or more. As shown in FIG. 5, a solder 103 is formed on the peripheral surface and the lead of the plug body by plating. The left side of the lead in the drawing is an inner lead, on which solder plated is heated to fix the piezoelectric vibrating reed. As shown in FIG. 6, the case body 105 is preferably plated with the same solder. It has been found that there is a problem that when the plug body and the case body are plated, an organic component in the plating solution is mixed into the solder 103. Therefore, if the piezoelectric vibrating reed 102 is sealed in the case body by airtight press-fitting as it is, a high temperature (normal temperature to 2
Extreme increase in equivalent resistance value (100 ° C.)
% In some cases), remarkable frequency aging occurs, and when incorporated in an oscillation circuit, oscillation may stop. In the present invention, when the solder-plated plug body is vacuum-pressed into the case body, heating baking is performed. The organic components caught in the solder 103 by the heat baking can be released to the outside.
At this time, the baking temperature is a temperature in a hatched portion surrounded by a eutectic line ab, a liquidus line ac, and a line having a lead content of 90% or more in FIG. 7. It is possible to release the components sufficiently. As a result, the increase in the equivalent resistance value at a high temperature is kept within several percent. As a first specific example of the structure of the piezoelectric oscillator, as shown in FIG. 1B, a piezoelectric vibrator 1 and a semiconductor device (IC) 2 for electrically oscillating the piezoelectric vibrator 1 are provided. An oscillation circuit is formed by electrically connecting the piezoelectric vibrator 1 and the semiconductor device 2 by a thin metal wire 9 formed by wire bonding via a metal lead 5 and an alloy layer 7 including a solder 103 by welding via a metal lead 5. ing. Further, the piezoelectric vibrator 1, the semiconductor device 2, the metal leads 5, and the thin metal wires 9 are formed of the resin 8. As a second specific example of the structure of the piezoelectric oscillator, as shown in FIGS.
And a semiconductor device 2 for electrically oscillating the piezoelectric vibrator 1 are arranged in a front-to-back relationship with respect to the metal frame 3, and the tab 4 of the metal frame 3 to which the semiconductor device 2 is fixed is attached.
Are pushed out toward the piezoelectric vibrator 1 and are in parallel contact with the piezoelectric vibrator 1 to ensure electrical insulation clearance between the piezoelectric vibrator 1 and the plurality of metal leads 5. This prevents not only electrical continuity between the piezoelectric vibrator 1 and the plurality of metal leads 5 but also short-circuit between the metal leads 5. With this structure, as compared with the case where the piezoelectric vibrator and the semiconductor device are arranged in the plane direction, the assembly is made to be about １ ／ in the plane and the minimum total thickness of the components in the thickness direction. Further, the lead 6 of the piezoelectric vibrator 1 is connected to the metal lead 5 related to the electric oscillation by the solder 1 shown in FIG.
03 is welded as an alloy layer 7 containing the same. Although the lead 6 does not necessarily require solder plating, the lead 6 is plated simultaneously with the inner side 104 when the solder plating 103 is performed on the plug body shown in FIG.
The solder 103 is welded to the metal lead 5 with the solder 103 attached as an alloy layer containing the solder 103. Finally, the entire structure including the piezoelectric vibrator 1, the semiconductor device 2, the metal leads 5 and the tabs 4 is formed of a heat-resistant resin 8. As described above, the assembly diagram of the piezoelectric oscillator described in the embodiment is shown in FIG. 2 in which the soldering portion 106 of the vibrating reed 102, the case 105 and the plug portion FIG. The connecting portions between the leads 6 and the metal leads 5 of the vibrator all have a heat resistance of 260 ° C. or more including the components. The overall shape of the embodiment is an SMT-compatible flat package SOP type as shown in FIG. 1, but application to a DIP type as an insertion part is also mentioned as an embodiment. An example of application of the flat package to a J-BEND lead type is also given. As described above, according to the present invention,
The sides of the plug body and the entire surface of the inner lead are plated with solder using a plating solution containing an organic component, and the solder plated on the inner lead is heated to fix the piezoelectric vibrating reed to the inner lead. It is simple, and the vibrating reed and the inner lead need only be brought into light contact with each other when the vibrating reed is fixed, and the vibrating reed and the inner lead can be connected without leaving any stress on the vibrating reed. In addition, heat resistance can be imparted by performing solder plating using lead-tin solder having a lead content of 90% or more. Furthermore, the plug body and the case body with the piezoelectric vibrating reed fixed to the inner lead are baked in a vacuum atmosphere, and the plug body is hermetically press-fitted into the case body using solder plated on the side of the plug body as a sealing material. An organic component in the solder is removed, and a piezoelectric vibrator having a small equivalent resistance, excellent high-temperature aging characteristics, and high heat resistance can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is a perspective view of a first specific example of a piezoelectric oscillator using the present invention, and FIG. 1B is a cross-sectional view of a main part of FIG. 1A. is there. 2A is an assembly plan view of a main part of a second specific example of a piezoelectric oscillator using the present invention, and FIG. 2B is a plan view of FIG.
It is sectional drawing of the principal part of FIG. FIG. 3 is a sectional view of an embodiment of the piezoelectric vibrator of the present invention. FIG. 4 is a sectional view of a vibrating reed of the piezoelectric vibrator in FIG. 3; FIG. 5 is a sectional view of a plug body of the piezoelectric vibrator in FIG. 3; 6 is a sectional view of a case body of the piezoelectric vibrator in FIG. FIG. 7 is a state diagram of solder. FIG. 8 is a perspective view of a conventional piezoelectric oscillator. FIG. 9 is a main sectional view of a conventional piezoelectric oscillator. FIG. 10 is a sectional view of a conventional piezoelectric vibrator. [Description of Signs] 1 ... Piezoelectric vibrator, 2 ... Semiconductor device (IC), 3 ... Metal lead frame, 4 ... Tab of lead frame, 5 ... Plural leads of lead frame, 6 ... Lead terminal of piezoelectric vibrator, 7: alloy layer containing solder, 8: resin, 9: thin metal wire, 11: piezoelectric vibrator, 12: semiconductor device, 18: resin, 101: electrode, 102: piezoelectric vibrating piece, 103: 90
%: Lead containing at least% lead, 104: inner lead of plug body, 105: case body, 106: soldered portion of piezoelectric vibrating reed, 107: press contact or welding flange.

Claims (1)

(57) [Claims] The side surface of the plug body and the entire surface of the inner lead are plated with lead-tin solder having a lead content of 90% or more by solder plating using a plating solution containing an organic component, and the solder plated on the inner lead is heated. Then, the piezoelectric vibrating piece is fixed to the inner lead, the piezoelectric vibrating piece is baked in a vacuum atmosphere with the plug body and the case body fixed to the inner lead, and the solder plated on the side surface of the plug body is removed. A method for manufacturing a piezoelectric vibrator, wherein the plug body is hermetically press-fitted into the case body as a sealing material.