JPH05243471A - Piezoelectric oscillator - Google Patents

Abstract

PURPOSE:To obtain a plastic molded piezoelectric oscillator of a flat package type having leads or terminals. CONSTITUTION:An IC chip 2 is mounted on an island part 1, and a crystal resonator 5 is fixed on the surface facing the mounting surface of the chip 2. The injection port 9 of a resin package is arranged on a diagonal line. A cylindrical case 7 of the crystal resonator 5 is positioned in the range of + or -45 deg. to the injection port direction. Fixing parts to lead terminals 3 of the crystal resonator 5 and pads of the IC chip 2 are positioned in the diagonal line direction. The piezoelectric oscillator is packaged with resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-encapsulated piezoelectric oscillator having leads or terminals.

[0002]

2. Description of the Related Art Conventionally, there is no piezoelectric oscillator having a flat package piezoelectric vibrator built therein. As an example of the flat package, a PLCC (QFJ) -shaped semiconductor element has an IC chip 52 mounted on a central island portion 51 as shown in a plan view of FIG. 5A and a side view of FIG. The pads of the chip 52 and the lead terminals 53 that surround the four sides of the island portion 51 are connected by bonding wires 54. Resin molding is performed by a transfer molding method or the like while leaving the outside of the lead terminal 53. After that, the lead terminal 53 is obtained by cutting and bending.

[0003]

The conventional flat package type semiconductor device described above has the island portion 5
1 is surrounded by the lead terminals 53 and the resin package itself is thin, it is difficult to further mount the piezoelectric vibrator therein.

An object of the present invention is to solve the above problems of the prior art, and an object of the present invention is to provide a small and thin piezoelectric oscillator of high reliability resin package type. is there.

[0005]

The piezoelectric oscillator of the present invention comprises:
It is characterized in that at least one or more IC chips and one or more piezoelectric vibrators are fixed so as to face a lead frame and are made of resin. In addition, the IC on the surface of the island
The chip is mounted, and the piezoelectric vibrator having a cylindrical case is arranged and fixed on the opposing surface of the island portion.

Furthermore, at least one or more holes are provided on the outer surface of the resin package with the piezoelectric vibrator interposed between the opposite surfaces of the island.

Further, the resin injection port is provided on the diagonal line of the square package, and the longitudinal direction of the cylindrical case of the piezoelectric vibrator is set within a range of ± 45 ° with respect to the direction of the resin injection port. It is characterized by

Further, the present invention is characterized in that a pad for oscillating the piezoelectric vibrator of the IC chip is mounted on a diagonal line of the IC chip so that the IC pad is closer to the fixed part side of the piezoelectric vibrator.

Further, the island portion is die pad down (depressed) in the direction of the piezoelectric vibrator.

Further, the lead terminal for fixing the lead of the piezoelectric vibrator has a bent portion.

Further, the surface areas of the lead terminal fixing portion for fixing the lead of the piezoelectric vibrator and the peripheral lead terminal are made equal,
It is characterized in that the thermal conditions at the time of fixation are matched.

It is characterized in that the lead terminals to which the piezoelectric vibrators are connected are provided so as to be displaced from the arrangement positions of the other lead terminals so that the cutting die can be shared.

Further, the IC chip is an IC chip for a real-time clock and constitutes a real-time clock.

Further, the IC chip is a PLLIC chip and constitutes a PLL oscillator.

[0015]

EXAMPLE A plan view of FIG. 1 (a) and a cross section of FIG. 1 (b) showing an example of a piezoelectric oscillator of the present invention using a PLCC-shaped (QFJ-shaped) crystal oscillator using a crystal resonator as an example. It will be described with reference to the drawings.

The IC chip 2 is mounted on the island portion 1, and the pad of the IC chip 2 and the island portion 1 are mounted.
The lead terminals 3 surrounding the four sides of the are connected by bonding wires 4. The crystal oscillator 5 including a rectangular AT crystal oscillator piece or the like includes a lead 6 on the surface of the island portion 1 opposite to the mounting surface of the IC chip 2 and an electrode (CMOSI) for oscillating the crystal oscillator of the IC chip 2.
In the case of C or the like, it is fixed in the middle of the lead terminal 3 connected to the gate and drain terminal by welding, soldering, a conductive adhesive or the like. The longitudinal direction of the cylinder-shaped case 7 of the crystal unit 5 is aligned with the diagonal direction of the resin package 8 when completed. Crystal unit 5 and IC
The lead frame to which the chip 2 is attached (the above-mentioned island portion 1 and the lead terminal 3 fixed to one body) is set in a mold, and the resin is transferred by the transfer molding method while leaving the outside of the lead terminal 3. Seal with resin. After that, the lead terminal 3 is cut and bent to obtain a PLCC-shaped crystal oscillator. Here, the points of this embodiment will be described.

First, regarding the position of the crystal unit 5, PL
In order not to increase the thickness of CC, a crystal unit having a cylinder with an outer diameter of 2 to 1.5 [mm], particularly a tuning fork type crystal unit such as 32 KHz, is mounted on the IC chip 2 of the island section 1.
Provided on the surface opposite to the mounting surface. Further, it is desirable that the longitudinal direction of the cylindrical case 7 be a diagonal direction of the resin package 8. The reason for this is that the resin injection ports 9 such as transfer molds are provided at the corners of the diagonal lines because the lead terminals 3 are arranged at the same pitch in four directions. If the longitudinal direction of the shaped case 7 is aligned with the longitudinal direction of the shaped case 7, excessive pressure is not applied to the cylindrical shaped case 7 when the resin is injected, and no force is applied to the fixing portion 11 of the lead terminal 3 of the lead 6 of the crystal unit 5. Therefore, the lead terminal 3 may be deformed (in the worst case, a malfunction may occur such as a short-circuit with the adjacent lead terminal),
The problem that the position of the crystal unit 5 itself moves does not occur.

It should be noted that the cylinder-shaped case 7 has a degree of freedom of design with respect to the direction of the injection port, but not within the range of ± 45 °, preferably ± 30 °.

The crystal unit 5 has a cylindrical case 7 facing the island 1.
This is because the PLCC surrounds the four sides of the island portion 1 with the lead terminals 3. Therefore, disposing the crystal oscillator 5 in the lead frame other than the island portion 1 prevents the positional deviation during the transfer molding. It is difficult to consider.

Further, as shown in FIG. 1, a pin for fixing the cylinder-shaped case 7 to the mold is provided so that the cylinder-shaped case 7 of the crystal unit 5 does not protrude to the surface of the resin package. Good to mold. Due to the pins provided in the mold, the completed piezoelectric oscillator is provided with holes 11 on the opposing surfaces of the resin package island 1 and the cylindrical case 7.

The fixed portion 10 of the lead 6 of the crystal resonator 5 of the lead terminal 3 is preferably provided with a bent portion so as to have a spring property. This purpose is to fix the lead 6 of the crystal unit 5 to the fixing portion 10 by welding or the like, but to prevent the influence at that time from being transmitted to the wire bonding portion at the tip of the lead terminal 3. .

Further, in order to make the thermal conditions of the two fixing parts 10 uniform, the fixing parts 10 and the peripheral lead terminals are designed to have the same surface area, so that the fixing work such as welding becomes stable. Can be done. Therefore, the lead terminal may be designed in a curved shape as in this embodiment.

As shown in FIG. 2, the gate and drain pads 21 and 22 of the IC chip 2 are provided in the diagonal direction of the IC chip 2, that is, in the vicinity of one of the four corners. When the IC chip 2 is mounted on the island portion 1 with the wiring 22 facing the lead terminal 3 to which the crystal resonator 5 is fixed, the wiring for the gate and the drain becomes the shortest distance, and wire bonding becomes easy. Further, as a result of shortening the length of the gate and the drain, it becomes effective for high frequencies, less noise is radiated to the outside, and noise from the outside is not received, so that a highly reliable device can be obtained.

Further, as shown in FIG. 3, the lead terminals 23 to which the crystal unit 5 is fixed are taken out at other PL positions.
The CC-shaped semiconductor elements are provided at regular pitches, offset from the positions having the lead terminals.

This is because the cutting die can be shared, which is an effective method for mass production.

Further, as shown in FIG. 4, even if the recess 24 of the lead is provided in the portion having no lead terminal, no functional obstacle occurs.

Since a mold for a package having lead terminals on all can be shared, similarly, new arrangement of mass production equipment is not required.

Further, the island portion 1 is provided with another lead terminal 3
When it is submerged from the position of the crystal oscillator 5 side (called die pad down or depress), the distance between the lead terminal 3 and the pad of the IC chip 2 becomes short, and the length of the entire wire bonding line is increased. In addition to shortening, the risk of the lead terminal 3 coming into contact with the cylindrical case 7 can be avoided. This is less of a problem when the size of the cylindrical case 7 is smaller than the size of the island part 1, but when the positional deviation of the crystal unit 5 occurs and when the size of the cylindrical case 7 is larger than the island part 1. 1
It is effective when the size is larger than.

As described above, regarding the piezoelectric oscillator of the present invention, PL
CC {QFJ (Quad FlatJ-Lead Pa
Although an example of a crystal oscillator having a shape of a CFPs) has been described, the present invention is not limited to this, and QFP (Qua
d Flat Packages), QFI (Quad)
Flat I-Lead Packages), QF
N (Quad Flat Non-Lead Pack)
ages), SOP (Small Outline P)
ACKAGES), SOJ (Small Outlin)
e J-Lead Packages), DIP (Du
It can be applied to packages such as al In-Line Packages) in which leads and terminals are exposed.

FIG. 6 shows an embodiment of the QFP type crystal oscillator. The package structure is the same as that of the PLCC type crystal oscillator of FIG. However, the shape of the outer lead 72 is different.

FIG. 7 shows an embodiment of a SOP type crystal oscillator. The package structure is the same as that of the PLCC type crystal oscillator of FIG. However, the outer lead 92 extends from only two directions of the package.

Further, FIG. 8 shows an embodiment in which a hole 102 is provided on the surface side of the package 101.

Since the piezoelectric oscillator of the present invention has a large number of terminals, it can be applied to a multi-frequency output oscillator having many frequency division stages, a computer peripheral device such as a real-time clock, and a phase-locked loop (PLL) crystal oscillator. Use of is desirable.

The real-time clock is a circuit that sends clock information to a computer.
[Hz] is used to divide the oscillation frequency of the tuning fork type oscillator to create hours, minutes, seconds, and data, and transfer it to the CPU of the computer, which requires many input / output terminals for data transfer. So suitable.

When configuring a PLL crystal oscillator,
A crystal oscillator is used as a reference signal, and in this example, 2.0 [mm]
A rectangular AT crystal unit of φ is used to prevent the package thickness from increasing, but 3.0 if necessary.
A rectangular AT crystal oscillator of [mm] φ is used.

As for the structure of the PLL crystal oscillator, it is preferable that the above-mentioned crystal oscillator is used as a reference signal, a plurality of PLL circuits are combined, and a plurality of outputs are taken out in one package.

By arbitrarily setting the division ratio of each PLL circuit, the clock signal (the reference signal may be output as it is) required in the computer, and
Simultaneously outputs several kinds of signals such as graphic signals.
A single PLL crystal oscillator provides a crystal oscillator that covers all signals.

[0038]

As described above, according to the piezoelectric oscillator of the present invention, in a flat package resin package, I
Since the piezoelectric crystal oscillator having a cylindrical case is positioned and fixed on the surface of the IC chip on which the C chip is mounted facing the IC chip, a piezoelectric oscillator having substantially the same size as a flat packaged semiconductor device can be obtained.

In general, if the resin package is left unattended,
Water is absorbed by the storage environment.

When solder mounting is performed in this state, moisture around the cylindrical case vaporizes and expands, the water vapor pressure rises, and stress concentrates on the thinnest portion of the mold.

However, according to the present invention, the holes provided on the back surface or the front surface of the resin package allow the moisture due to the moisture absorption of the resin package to be released to the outside, thereby preventing the generation of the package crack due to the thermal stress at the time of solder mounting. It is possible to obtain a highly reliable piezoelectric oscillator.

If a resin injection port is provided in the diagonal portion of the resin package and the cylindrical case of the piezoelectric vibrator is mounted within a range of ± 45 ° (preferably ± 30 °) with respect to the diagonal direction, the resin is injected. A force is applied to the piezoelectric vibrator at the time of injection, and problems such as positional displacement and short-circuiting of lead terminals do not occur.

Further, if a pad for oscillating the piezoelectric vibrator of the IC chip is provided in the vicinity of the diagonal line, the connection distance with the piezoelectric vibrator becomes the shortest, and it becomes strong against noise intrusion and leakage.

Furthermore, if the island portion is die put down (also referred to as depress) on the piezoelectric vibrator side, there is a risk that the piezoelectric vibrator cylinder-shaped case may come into contact with the lead terminal to cause a short circuit defect. A piezoelectric oscillator that can be avoided and has high reliability can be obtained.

It should be noted that it is effective to prevent the above-mentioned short circuit with the lead terminals by positioning the cylinder-shaped case of the piezoelectric vibrator near the island portion and not providing it near the lead terminals.

Further, since the lead terminal for fixing the lead of the piezoelectric vibrator is provided with the bent portion, when the piezoelectric vibrator is fixed,
Reliability is improved because the shock during processing is not transmitted to the bonding wire.

Further, in order to make the thermal conditions of the fixed portion uniform,
Since the fixing portion and the peripheral lead terminals are designed to have the same surface area, the fixing work can be stably performed.

Further, since the lead terminals for fixing the crystal unit are provided so that the arrangement positions of the other lead terminals are shifted, the cutting die can be shared and it is not necessary to arrange a new manufacturing apparatus.

Further, the mold of the package can be shared.

Further, according to the present invention, in the PLL oscillator, since the PLL IC and the crystal are connected at the shortest distance to obtain the reference clock with less noise, the signal purity of the signal output from the VCO is good.

That is, when the reference signal is generated outside the PLL IC, noise is overlapped with the reference signal due to interference of other clocks or signals. If the PLL is operated with this noise-blended reference clock, the signal purity of the VCO output will also deteriorate. Furthermore, since the reference clock is not required to be laid around, the power can be reduced.

Further, mutual interference between the PLL IC and the crystal oscillator is eliminated, the signal purity is improved, the stable operation of the PLL circuit is obtained, and the highly reliable PLL oscillator is obtained.

Further, since the reference clock is not laid around, radiation noise is reduced, and high quality and high reliability P is achieved.
An LL oscillator is obtained.

[Brief description of drawings]

FIG. 1 illustrates a PL as an embodiment of a piezoelectric oscillator of the present invention.
The figure which shows a CC (QFJ) -shaped crystal oscillator. (A) is a plan view. (B) is a side view.

FIG. 2 is an enlarged view of the vicinity of the connection between the crystal unit and the IC.

FIG. 3 is an enlarged view showing positions of lead terminals for fixing the crystal unit.

FIG. 4 is a diagram showing an embodiment of a crystal oscillator using a mold for a package having lead terminals on the entire circumference.

FIG. 5 shows a conventional semiconductor device including a PL
The figure which shows a semiconductor element of CC (QFJ) shape. (A) is a plan view. (B) is a side view.

FIG. 6 is a diagram showing a QFP-shaped crystal oscillator as another embodiment.

FIG. 7 is a diagram showing a SOP type crystal oscillator as another embodiment.

FIG. 8 is a view showing a QFP-shaped crystal oscillator in which holes are provided on the package surface.

[Explanation of symbols]

 1,51 Island part 2,52 IC chip 3,53 Lead terminal 4,54 Bonding wire 5 Crystal oscillator 6 Lead 7 Cylinder type case 8 Resin package 9 Injection port 10 Fixing part 11 Hole

Claims (11)

[Claims] 1. At least one or more IC chips and one or more piezoelectric vibrators are fixed facing a lead frame,
A piezoelectric oscillator characterized by being molded with resin. 2. The IC chip is mounted on the surface of the island portion, and the piezoelectric vibrator having a cylindrical case is arranged and fixed on the opposing surface of the island portion. Piezoelectric oscillator. 3. The piezoelectric oscillator according to claim 2, wherein at least one or more holes are provided on the opposite surface of the island with the piezoelectric vibrator sandwiched between the outer surfaces of the resin package. 4. A resin injection port is provided on a diagonal line of a square package, and a longitudinal direction of a cylindrical case of the piezoelectric vibrator is set within a range of ± 45 ° with respect to the direction of the resin injection port. The piezoelectric oscillator according to claim 3, wherein 5. The pad for oscillating a piezoelectric vibrator of an IC chip is mounted on a diagonal line of the IC chip and mounted in a direction in which an IC pad is close to a fixed portion side of the piezoelectric vibrator. Piezoelectric oscillator. 6. The piezoelectric oscillator according to claim 2, wherein the island portion is die pad down (depressed) in the direction of the piezoelectric vibrator. 7. The piezoelectric oscillator according to claim 2, wherein a lead terminal for fixing the lead of the piezoelectric vibrator has a bent portion. 8. The piezoelectric oscillator according to claim 2, wherein the surface area of the fixing portion of the lead terminal for fixing the lead of the piezoelectric vibrator and the peripheral lead terminal are made equal, and the thermal conditions at the time of fixing are made to coincide. .. 9. The piezoelectric element according to claim 4, wherein the lead terminal to which the piezoelectric vibrator is connected is provided so as to be displaced from the arrangement position of the other lead terminals so that the cutting die can be shared. Oscillator. 10. The IC chip is an I for real-time clock.
The piezoelectric oscillator according to claim 1, wherein the C chip constitutes a real-time clock. 11. The IC chip is a PLLIC chip, P
The piezoelectric oscillator according to claim 1, which constitutes an LL oscillator.