JP3000917B2 - Piezoelectric oscillator - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric oscillator in which a piezoelectric vibrator and an oscillation circuit are housed in a single package. 2. Description of the Related Art The configuration of a conventional piezoelectric oscillator will be described with reference to a plan view of FIG. 4A and a front sectional view of FIG. 4B, taking a crystal oscillator using a crystal oscillator as an example. FIG. 4 (a),
3B, the semiconductor element 41 and the semiconductor element 41
The lead terminals 43 connected by wire bonding with the Au thin wires 42 are resin-packaged 50 by transfer molding. The fixing position of the crystal unit 44 is determined with respect to the longitudinal direction of the resin package.
The transfer mold is in a projecting shape (not shown) in advance, and has a concave shape after resin molding. The crystal oscillator is put into the recess, and the lead wire of the crystal oscillator is connected and fixed to the crystal oscillator connection lead terminals 45 and 46 by soldering 47 or the like. Further, a configuration is adopted in which a resin 48 such as epoxy is filled to fill the quartz oscillator 44 and the recesses around it and dried. However, in the above-mentioned prior art, the size (thickness) of the outer edge of the concave portion is required at the time of packaging, so that the size of the package has been increased. Furthermore, since there is a large interface between the resin such as epoxy filled in the concave portion and the transfer mold resin, there is a problem that abnormal oscillation of the piezoelectric vibrator occurs due to moisture penetrating the interface. I was Accordingly, the present invention is intended to solve such a problem. It is an object of the present invention to provide an oscillator having excellent moisture resistance by preventing penetration of moisture and the like, which is further reduced in size. It is. [0005] A piezoelectric oscillator according to the present invention comprises:
A piezoelectric oscillator in which a semiconductor element and a cylindrical piezoelectric vibrator are housed in a package, wherein the semiconductor element and the piezoelectric vibrator are arranged in parallel with respect to a longitudinal direction of the package, The lead terminal inside the piezoelectric oscillator and the semiconductor element are connected by bonding along the longitudinal direction of the piezoelectric vibrator, and the resin is injected from a resin injection port arranged toward the end face of the piezoelectric vibrator. The package is formed by transfer molding. FIG. 1A shows a piezoelectric oscillator according to an embodiment of the present invention, taking a crystal oscillator using a crystal oscillator as an example.
This will be described with reference to FIG. FIG. 1A is a plan view, and FIG.
4B is a front sectional view, in which the semiconductor element 1 is fixed on the die pad 3 of the lead frame and wire-bonded with the Au wire 2 to connect the lead terminals 7 and 8 to each other.
(In this example, six lead terminals will be described, but any number of lead terminals may be used.) The lead terminal 7 is a lead terminal for connecting two crystal units, and one end of the lead terminal 7 is connected to the semiconductor element 1 by Au wire bonding.
The other end is provided with a crystal oscillator connection pad 5 and then extendedly connected to a lead frame outer frame 6, and the lead of the cylindrical crystal oscillator 4 is placed on the crystal oscillator connection pad 5. The wire 10 is fixed by soldering 9. The other lead terminals 8 are extended to become outer leads 13. As described above, the semiconductor element 1, the Au wire 2, the quartz oscillator 4,
Each of the lead terminals 7, 8 and the like is repackaged by a resin injected from an injection port 11 by transfer molding using an epoxy resin or the like. The injection port 11 is arranged toward the end face of the crystal unit 4, and this is achieved by injecting the mold resin toward the crystal unit 4, so that a thin portion is formed before the curing of the mold resin starts. That is, the thickness is further reduced by filling the apex portion of the crystal unit 4. The temperature of the transfer molding is determined by the members constituting the crystal unit shown in FIG. 2, in particular, the fixed portion between the crystal unit 21 and the plug lead 22, the cylindrical cap 24, and the plug 25.
Temperature lower than the melting point of the solder 23 used for the sealing portion 26 and the like (the melting point of the solder used in this example is 18
Although the temperature is 3 ° C., the temperature at which solder actually softens and becomes a problem is around 175 ° C. from the experimental value, and the transfer mold temperature is set to 170 ° C. or less with a margin. ). Further, as shown in FIG. 3, the semiconductor element 31 and the crystal oscillator 32 are arranged in parallel to the longitudinal direction of the crystal oscillator 32 so that they are parallel to each other.
4 (represented in the figure as a representative) is bonded to the longitudinal direction of the crystal unit 32 by bonding with an Au wire 33, so that the dimension in the width direction can be reduced. By using a quartz crystal resonator, only the top of the cylinder is thinned, and the other parts can be kept thick, minimizing the package thickness, and significantly reducing the overall package dimensions. Can be. Although the package shape shown in this embodiment has been described in the DIP shape, the effect is not limited to the DIP shape, and the same effect can be obtained by, for example, a SIP shape, SOJ shape, SOP shape, or the like. Further, the vibrator is not limited to the crystal vibrator shown in the embodiment, but may be a piezoelectric oscillator using a lithium tantalate vibrator, a lithium molybdate vibrator, a ceramic vibrator or the like. Further, as for the form of the vibrator, in addition to the cylinder type shown in the embodiment, a flat type using ceramic, glass or the like or a chip type, which is advantageous for surface mounting, may be used. According to the piezoelectric oscillator of the present invention described above, the components are formed in the same package by molding the package at a temperature lower than the melting point of the components of the piezoelectric vibrator. Since the piezoelectric vibrator is housed, there is no deterioration of the piezoelectric vibrator, foreign matter such as moisture is prevented from entering, and the humidity resistance is greatly improved. Furthermore, since molding is completed at the same time, resin filling by conventional potting or the like becomes unnecessary, which reduces the number of processing steps, and eliminates the need for a recess for charging a resin by loading a piezoelectric vibrator. The thickness of the resin can be reduced as compared with the prior art, so that the size can be reduced. Further, by arranging the piezoelectric vibrator and the semiconductor element in parallel, the size in the longitudinal direction of the package can be reduced, and by connecting the semiconductor element and the lead terminal along the longitudinal direction of the piezoelectric vibrator,
The width dimension of the package can be reduced.
Also, if a cylindrical crystal unit using a cylindrical cap is used, only the top of the cylinder is thinned and the other parts are kept thick, so the package thickness can be reduced and the package thickness can be reduced. Dimensions can be reduced. The resin injection port is arranged toward the end face of the piezoelectric vibrator, so that the mold resin is injected toward the piezoelectric vibrator, so that the piezoelectric resin having a small thickness can be formed before the curing of the mold resin starts. By filling the top part of the vibrator, insufficient filling of the same part can be prevented,
Further, the thickness of the same portion can be further reduced, and a piezoelectric oscillator with a small mold thickness can be obtained. Therefore, by using the configuration of the present invention, it is possible to provide the most compact piezoelectric vibrator having excellent moisture resistance at low cost.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is a plan view and FIG. 1B is a front sectional view of a crystal oscillator as one embodiment of a piezoelectric oscillator of the present invention. FIG. 2 is a cross-sectional view illustrating a configuration of a crystal resonator according to an embodiment of the present invention. FIG. 3 is a sectional view in a plan layout view showing another embodiment of the present invention. 4A and 4B show a crystal oscillator as one example of a conventional piezoelectric oscillator, wherein FIG. 4A is a plan view and FIG. 4B is a front sectional view. [Description of Signs] 1 ... Semiconductor element 2 ... Au wire 3 ... Die pad 4 ... Crystal resonator 5 ... Crystal resonator connection pad 6 ... Lead frame outer frame 7 ...・ Crystal resonator connection lead terminal 8 ・ ・ ・ Lead terminal 9 ・ ・ ・ Solder 10 ・ ・ Crystal resonator lead wire

Claims (1)

(57) [Claims] A piezoelectric oscillator comprising a semiconductor element and a cylindrical piezoelectric vibrator housed in a package, wherein the semiconductor element and the piezoelectric vibrator are arranged in parallel to a longitudinal direction of the package, and A lead terminal inside a piezoelectric oscillator and the semiconductor element are connected by bonding along the longitudinal direction of the piezoelectric vibrator, and a resin injected from a resin injection port arranged toward an end face of the piezoelectric vibrator is used. A piezoelectric oscillator, wherein the package is formed by transfer molding.