JP2006101090A - Method for adjusting frequency of piezoelectric oscillator, piezoelectric oscillator and electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small and highly accurate piezoelectric oscillator.
A piezoelectric oscillator (10) includes a piezoelectric vibrating piece (12) and an IC chip (14) that oscillates a piezoelectric vibrating piece (12) having a larger plane size than the piezoelectric vibrating piece (12). 12 is mounted on the bottom of the package 16 so as to face the hole provided on the bottom surface of the package 16 for frequency adjustment and airtight sealing, and the IC chip 14 is a piezoelectric vibrating piece. 14 is provided above 14.
[Selection] Figure 1

Description

  The present invention relates to a frequency adjustment method for a piezoelectric oscillator, a piezoelectric oscillator, and an electronic apparatus, and more particularly to a frequency adjustment method suitable for a small piezoelectric oscillator.

Piezoelectric oscillators are mounted on various electronic devices and are used as reference frequency sources and reference signal sources. The piezoelectric oscillator has a configuration in which, for example, a piezoelectric vibrating piece and a circuit component having a size larger than that of the piezoelectric vibrating piece are arranged vertically in a recess of the package, and a lid for hermetically sealing the inside of the package is provided on the upper surface of the package. There is what is joined (for example, refer to patent documents 1). The piezoelectric oscillator has a configuration in which a piezoelectric vibrating piece is mounted on the bottom of a package base, an IC chip is mounted on the package base above the piezoelectric vibrating piece, and a lid is joined to the top of the package base. (For example, refer to Patent Document 2).
JP 2001-217650 A JP 2004-135190 A

  However, in recent years, as electronic devices on which piezoelectric oscillators are mounted are downsized, piezoelectric oscillators are also downsized. For this reason, the piezoelectric vibrating piece and the IC chip mounted on the piezoelectric oscillator are also downsized. However, when a circuit having an additional function such as a temperature compensation circuit is mounted on the IC chip, there is a limit to downsizing the IC chip. There is. Accordingly, since the piezoelectric vibrating piece is smaller than the IC chip, in the piezoelectric oscillator having the configuration in which the IC chip is mounted on the bottom of the package base and the piezoelectric vibrating piece is mounted on the package base above the IC chip, Miniaturization could not be realized.

  As an example of the frequency adjustment method of the piezoelectric oscillator, after adjusting the frequency by changing the mass of the excitation electrode formed on the piezoelectric vibrating piece, the lid is joined to the upper surface of the package base to hermetically seal the inside of the package, Thereafter, there is a method of performing further frequency adjustment with a capacitor array mounted on the IC chip. However, in the piezoelectric oscillator in which the piezoelectric vibrating piece is mounted on the bottom of the package base and the IC chip is mounted on the package base above the piezoelectric vibrating piece, the IC chip is disposed above the piezoelectric vibrating piece. Irradiating ions or the like to the excitation electrode of the vibrating piece to reduce the mass, or attaching a metal to the excitation electrode to increase the mass, it was impossible to perform accurate frequency adjustment.

Figure 10 is a graph showing the relationship between the oscillation frequency f of the capacitance C _L and the piezoelectric oscillator of the capacitor array provided on the IC chip. The solid line is a characteristic curve when the plane size of the piezoelectric vibrating piece is large, and the broken line is a characteristic curve when the plane size of the piezoelectric vibrating piece is small. When the plane size of the piezoelectric resonator element mounted on the piezoelectric oscillator is large, the frequency range Ra that can be adjusted by the capacitor array is wide. However, when the plane size of the piezoelectric resonator element is small, the frequency range Rb that can be adjusted by the capacitor array is narrow. Become. Therefore, due to variations in the oscillation frequency of the piezoelectric oscillator, there arises a problem that a desired frequency does not fall within the frequency range adjustable by the capacitance adjustment array, and many piezoelectric oscillators that cannot be adjusted only by the capacitance array are manufactured. For example, when the piezoelectric oscillator is a temperature compensation type, if the plane size of the piezoelectric vibrating piece is large, the temperature value of the frequency temperature characteristic can be adjusted and the frequency deviation at normal temperature can be adjusted with a capacitance value that can be adjusted by the capacitance array. However, if the plane size of the piezoelectric vibrating piece is reduced, the frequency adjustment range is narrowed even with the same capacitance array as described above, and therefore temperature compensation of frequency temperature characteristics and adjustment of frequency deviation at room temperature cannot be performed. It was.

  An object of the present invention is to provide a method for adjusting the frequency of a piezoelectric oscillator. It is another object of the present invention to provide a small and highly accurate piezoelectric oscillator. Furthermore, it aims at providing the electronic device carrying this piezoelectric oscillator.

  In order to achieve the above object, a method for adjusting a frequency of a piezoelectric oscillator according to the present invention includes a step of mounting a piezoelectric vibrating piece on a bottom portion of a package base, and a circuit for oscillating the piezoelectric vibrating piece. A step of mounting above the piece, a step of sealing the upper portion of the circuit, a step of adjusting the frequency of the piezoelectric vibrating piece through a hole provided in the bottom surface of the package base, and the hole And a step of sealing. In this case, the frequency adjustment of the piezoelectric vibrating piece is performed by adjusting the mass of the excitation electrode provided on the piezoelectric vibrating piece. The excitation electrode can be lightened by being irradiated with high-energy particles through the hole, and can be made heavy by being attached with metal through the hole. The step of sealing the circuit may be a step of bonding a lid to the upper surface of the package base or a step of sealing the upper portion of the circuit with a molding material.

  Accordingly, even if the piezoelectric vibrating piece is disposed on the lower side of the circuit and mounted on the package base, the frequency of the piezoelectric vibrating piece can be adjusted using the hole provided on the bottom surface of the package base. Further, since the heat and gas generated when sealing the hole are extremely small, the heat and gas do not adversely affect the oscillation frequency of the piezoelectric oscillator, and a piezoelectric oscillator with high frequency accuracy can be obtained. .

  The piezoelectric oscillator according to the present invention includes a piezoelectric vibrating piece and an IC chip that oscillates the piezoelectric vibrating piece and is larger in size than the piezoelectric vibrating piece, and the piezoelectric vibrating piece is an excitation electrode provided on the piezoelectric vibrating piece. Is mounted on the bottom of the package so as to face the hole provided on the bottom of the package for frequency adjustment and hermetic sealing, and the IC chip is provided above the piezoelectric vibrating piece. Yes.

  The piezoelectric vibrating piece has a smaller planar size than the IC chip. Therefore, the piezoelectric oscillator can be reduced in size because the piezoelectric resonator element is disposed on the lower side and the IC chip is disposed on the upper side and mounted on the package. Further, the mass of the excitation electrode provided on the piezoelectric vibrating piece can be adjusted using a hole provided opposite to the excitation electrode. As a result, the oscillation frequency of the piezoelectric oscillator is adjusted by adjusting the mass of the excitation electrode, so that a desired oscillation frequency can be obtained by adjusting the frequency of the piezoelectric oscillator using an IC chip.

  The IC chip is mounted on the package while hermetically sealing the piezoelectric vibrating piece. This eliminates the need to join the lid to the upper surface of the package base and hermetically seal the piezoelectric vibrating piece inside the package, so that the piezoelectric oscillator can be made thinner.

  The IC chip is sealed with a molding material. In this case, the electrical connection means between the IC chip and the package may be sealed with a molding material. Thereby, since the joint strength between the IC chip and the package can be improved, the impact resistance can be improved. In addition, since the electrical connection means, that is, the wire or the like is also sealed with the molding material, disconnection due to impact or the like can be prevented.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a method for adjusting a frequency of a piezoelectric oscillator, a piezoelectric oscillator, and an electronic device according to the present invention will be described below. First, the first embodiment will be described. FIG. 1 is an explanatory diagram of the piezoelectric oscillator according to the first embodiment. FIG. 1A is a sectional view of the piezoelectric oscillator, and FIG. 1B is a plan view of the piezoelectric oscillator. In FIG. 1B, the lid is omitted. The piezoelectric oscillator 10 according to the first embodiment has a configuration in which a piezoelectric vibrating piece 12 and a circuit (IC chip 14) that oscillates the piezoelectric vibrating piece 12 are housed in a package 16.

  The package base 18 on which the piezoelectric vibrating piece 12 and the IC chip 14 are mounted has a configuration including a recessed portion 20 inside, and the side surface of the recessed portion 20 is formed in a stepped shape. On the bottom surface of the package base 18, a mount electrode 22 for mounting the piezoelectric vibrating piece 12 is provided. Further, a sealing hole 24 penetrating the back surface of the package base 18 is provided on the bottom surface of the package base 18. The cross-sectional shape of the sealing hole 24 may be, for example, a circle, an ellipse, a rectangle, a triangle, or the like. Further, a mounting electrode 28 for mounting the IC chip 14 is formed on the upper surface of the step 26 formed on the side surface of the recessed portion 20. A part of the mounting electrode 28 is electrically connected to the mount electrode 22 via a wiring pattern (not shown).

  The piezoelectric vibrating reed 12 is smaller in size than the IC chip 14, and connection electrodes 32 are provided at both ends of the short side of the piezoelectric substrate 30, and an excitation electrode that is electrically connected to the connection electrode 32 at the center of the piezoelectric substrate 30. 34 is provided. The piezoelectric vibrating reed 12 is mounted on the package base 18 with the connection electrode 32 and the mount electrode 22 being electrically and mechanically connected via a conductive adhesive 36. At this time, the excitation electrode 34 of the piezoelectric vibrating piece 12 is located above the sealing hole 24 formed in the bottom surface of the package base 18. The piezoelectric vibrating piece 12 may be mounted on the package base 18 in a cantilevered manner or may be mounted on both the ends.

The circuit is integrated to form an IC chip 14. The IC chip 14 may be provided with a voltage control circuit and the piezoelectric oscillator may be a voltage control type, or a temperature compensation circuit may be provided and the piezoelectric oscillator may be a temperature compensation type. Further, the piezoelectric oscillator may be a voltage control-temperature compensation type by combining these circuits. The piezoelectric oscillator 10 may be mounted with a resistor, a capacitor, and the like together with the IC chip 14. The circuit is not limited to the structure formed by the IC chip 14 but may be a structure formed by a discrete circuit.
A lid 38 is joined to the upper surface of the package base 18.

  Next, a method for manufacturing the piezoelectric oscillator 10 and a frequency adjusting method will be described. First, after the piezoelectric vibrating reed 12 is mounted on the mount electrode 22 provided on the bottom surface of the package base 18 via the conductive adhesive 36, the IC is applied to the mounting electrode 28 provided on the step 26 of the recessed portion 20. Chip 14 is mounted. At this time, the IC chip 14 is mounted face down, and a pad (not shown) provided on the active surface of the IC chip 14 and the mounting electrode 28 are electrically and mechanically connected by flip chip bonding. A lid 38 is joined to the upper surface of the package base 18. At this time, when a metal lid is used, it is joined by seam welding or the like, and when a glass lid is used, it may be joined via a low melting point glass or the like.

  Next, in the piezoelectric oscillator 10, the mass of the excitation electrode 34 is adjusted through the sealing hole 24 provided on the bottom surface of the package base 18. That is, the frequency adjustment is performed, for example, after the piezoelectric oscillator 10 is placed in a vacuum vessel and covered with a mask that exposes the sealing hole 24, and then high energy is applied from an ion gun or a plasma gun provided below the piezoelectric oscillator 10. The excitation electrode 34 may be irradiated with this particle to the excitation electrode 34 through the sealing hole 24 to reduce the thickness of the excitation electrode 34. Thereby, the mass of the excitation electrode 34 becomes light. The oscillation frequency of the piezoelectric oscillator 10 may be adjusted by attaching a metal to the excitation electrode 34 using a film formation method such as sputtering or vapor deposition, and increasing the mass of the excitation electrode 34.

  Next, the sealing hole 24 provided on the bottom surface of the package base 18 is sealed with a sealing material. FIG. 2 is an explanatory diagram of hole sealing. Specifically, after the piezoelectric oscillator 10 is placed in a vacuum or in an inert gas atmosphere, the sealing material 40 is placed in the opening of the sealing hole 24. As the sealing material 40, for example, a metal ball made of a material such as gold-tin, gold-germanium, or silver solder may be used, and the diameter of the ball only needs to be larger than the opening of the sealing hole 24. . The sealing material 40 is melted by being irradiated with a laser beam or an electron beam, or by being brought into contact with a heating device, and seals the sealing hole 24. As a result, the inside of the package 16 of the piezoelectric oscillator 10 is hermetically sealed with a vacuum or an inert gas. When the sealing hole 24 is sealed with the sealing material 40, heat and gas are generated when the sealing material 40 is melted. However, heat generated when the lid 38 is joined to the package base 18 is reduced. Since the amount is smaller than the amount of gas, the amount by which the oscillation frequency of the piezoelectric oscillator 10 is shifted is extremely small.

  FIG. 3 is an explanatory diagram of the oscillation frequency distribution after assembly of the piezoelectric oscillator. In addition, the vertical axis | shaft of FIG. 3 has shown the frequency deviation. In FIG. 3, (1) an oscillation frequency distribution of a piezoelectric oscillator in which a piezoelectric vibrating piece is mounted on a package base and then a lid is bonded to the upper surface of the package base, and (2) a piezoelectric vibrating piece is mounted on the package base and excited. After adjusting the oscillation frequency by adjusting the mass of the electrode, the oscillation frequency distribution of the piezoelectric oscillator in which the lid is bonded to the upper surface of the package base, and (3) mounting the piezoelectric vibrating piece 12 on the package base 18, After the lid body 38 is bonded to the upper surface of the piezoelectric oscillator 10, the mass of the excitation electrode 34 is adjusted via the sealing hole 24, and the oscillation of the piezoelectric oscillator 10 according to this embodiment in which the sealing hole 24 is sealed with a sealing material. The frequency distribution is shown. From FIG. 3, in the case of (3) according to this embodiment, the distribution of the oscillation frequency is within a narrow range, but in the case of (2), the distribution of the oscillation frequency is wider than in the case of (3). ing. In the case of (1), the oscillation frequency distribution is wider than in the case of (2). That is, in the case of (1), since the oscillation frequency of the piezoelectric oscillator is not adjusted, the oscillation frequency distribution is extremely wide. In the case of (2), after adjusting the oscillation frequency, the lid is joined to the package base, so the oscillation frequency is shifted by the heat and gas generated when the lid is joined to the package base. The frequency distribution has become wider. On the other hand, in the case of (3), after adjusting the oscillation frequency, the sealing hole 24 is sealed and the package 16 is hermetically sealed. Since the amount of gas is very small, the oscillation frequency distribution is narrow. Therefore, when the frequency adjustment method of the piezoelectric oscillator 10 according to the present embodiment is used, it is possible to obtain the highly accurate piezoelectric oscillator 10.

Next, the frequency of the piezoelectric oscillator 10 is adjusted using the IC chip 14. For this frequency adjustment, for example, the piezoelectric oscillator 10 is provided with an external electrode (not shown) and an adjustment terminal (not shown) that are electrically connected to the IC chip 14, and a probe for writing data is applied to the external electrode and the adjustment terminal. This is done by writing data for adjusting the capacitance of the capacitance array mounted on the IC chip 14 or adjusting the voltage supplied to the variable capacitance diode via this probe. If the piezoelectric oscillator is a voltage control type, data for voltage control is written. If the piezoelectric oscillator is a temperature compensation type, data for temperature compensation is written. If the piezoelectric oscillator has a programmable function, it is used for control. Data is written.
Thereafter, the piezoelectric oscillator 10 is completed by performing an airtightness test, a characteristic inspection, marking, and the like.

  As described above, the piezoelectric oscillator 10 has the piezoelectric vibrating piece 12 mounted on the bottom of the package base 18, and the IC chip 14 larger in size than the piezoelectric vibrating piece 12 is mounted on the step 26 of the package base 18. And the IC chip 14 are arranged vertically, the piezoelectric oscillator 10 can be downsized.

  In the piezoelectric oscillator 10, the piezoelectric vibrating reed 12 is mounted on the bottom of the package base 18, the upper surface of the package base 18 is joined with the lid 38, and then the sealing hole 24 provided below the excitation electrode 34. Since the oscillation frequency is adjusted and manufactured, the influence of heat and gas generated when the package 16 is hermetically sealed is reduced, and a product with high oscillation frequency accuracy can be obtained.

  Further, the piezoelectric oscillator 10 can adjust the oscillation frequency by changing the mass of the excitation electrode 34 of the piezoelectric vibrating piece 12 even if the piezoelectric vibrating piece 12 is disposed below the IC chip 14 and mounted on the package base 18. The IC chip 14 can be used to adjust the oscillation frequency to a range that can be adjusted. Therefore, for example, even when the piezoelectric oscillator 10 is a temperature compensation type, the temperature compensation of the frequency temperature characteristics and the adjustment of the frequency deviation at room temperature can be performed, and a highly accurate temperature compensation type piezoelectric oscillator can be obtained. it can.

  The method for adjusting the oscillation frequency by the IC chip 14 can also be performed as follows. That is, as shown in FIG. 4, the piezoelectric oscillator 42 has a configuration in which a conductive film 44 is provided on the side surface of the sealing hole 24 and a wiring pattern 46 for conducting the conductive film 44 and the IC chip 14 is provided. When the sealing material for sealing the stop hole 24 is melted, the sealing material and the conductive film 44 may be electrically connected. The sealing hole 24 having such a configuration can be used instead of the adjustment terminal, and a probe is brought into contact with the sealing material sealing the sealing hole 24 so that the IC chip 14 is used for frequency adjustment. Can be written. Thus, since the sealing hole 24 can be used as a writing terminal, the terminal portion can be saved in space compared with the case where the writing terminal is provided on the side surface of the package, and the piezoelectric oscillator 42 can be downsized. Further, the sealing hole 24 can serve as a guide when contacting the probe.

  Next, a second embodiment will be described. FIG. 5 is a sectional view of the piezoelectric oscillator according to the second embodiment. In the second embodiment, since a modification of the piezoelectric oscillator according to the first embodiment will be described, the same reference numerals are given to the same components as those in the first embodiment, and the description thereof will be omitted or simplified. .

  The piezoelectric oscillator 50 according to the second embodiment differs from the piezoelectric oscillator according to the first embodiment in the IC chip mounting method. That is, in the piezoelectric oscillator 50 according to the second embodiment, the piezoelectric vibrating reed 12 is mounted on the bottom of the package base 18 and the IC chip 14 has an adhesive on the step 26 of the recessed portion 20 with the active surface facing upward. The lid body 38 is bonded to the upper surface of the package base 18. The IC chip 14 is electrically connected to the pad 51 provided on the active surface and the electrode 52 provided on the step 26 by wire bonding.

In such a piezoelectric oscillator 50, since the active surface of the IC chip 14 faces the opposite side of the piezoelectric vibrating piece 12, ions used when the active surface adjusts the mass of the excitation electrode of the piezoelectric vibrating piece 12. It is not exposed to etc. Therefore, at the time of frequency adjustment, the pad 51 and the like provided on the active surface are not exposed to ions or the like, and the IC chip 14 is not adversely affected.
The piezoelectric oscillator 50 according to the second embodiment can achieve the same effects as the piezoelectric oscillator according to the first embodiment.

  Next, a third embodiment will be described. FIG. 6 is a cross-sectional view of the piezoelectric oscillator according to the third embodiment. In the third embodiment, since a modified example of the piezoelectric oscillator according to the above-described embodiment will be described, the same reference numerals are given to the same components as those in the above-described embodiment, and the description thereof will be omitted or simplified.

  In the piezoelectric oscillator 54 according to the third embodiment, the piezoelectric vibrating piece 12 is mounted on the bottom of the package base 18, and the IC chip 14 is mounted on the step 26 of the recessed portion 20 with the active surface facing upward. The periphery of the IC chip 14 is sealed with a molding material 56 such as a resin. At this time, the IC chip 14 is mounted using a brazing material or the like so as to hermetically seal the piezoelectric vibrating piece 12, and wire bonding is performed between the pad 51 provided on the active surface and the electrode 52 provided on the step 26. Is applied and electrically connected. A wire 58 that connects the pad 51 and the electrode 52 is also sealed with a molding material 56.

  Such a piezoelectric oscillator 54 is manufactured as follows. That is, after the piezoelectric vibrating piece 12 is mounted on the bottom of the package base 18, the IC chip 14 is mounted on the step 26 of the recessed portion 20, and wire bonding is performed between the electrode 52 and the pad 51 provided on the active surface. Is done. After the piezoelectric oscillator 54 is placed in the mold, a molding material 56 that seals the IC chip 14 and the wire 58 is injected into the mold. Thereafter, the sealing hole 24 is sealed by changing the mass of the excitation electrode of the piezoelectric vibrating piece 12 using the sealing hole 24 to adjust the oscillation frequency. The oscillation frequency is adjusted using the IC chip 14.

  Thus, the piezoelectric oscillator 54 has a configuration in which the piezoelectric vibrating reed 12 is hermetically sealed with the IC chip 14 and does not use a lid, so that the piezoelectric oscillator 54 can be thinned.

In addition, since the active surface of the IC chip 14 faces the side opposite to the piezoelectric vibrating piece 12, the active surface of the piezoelectric oscillator 54 is exposed to ions used when adjusting the mass of the excitation electrode of the piezoelectric oscillator 54. It will not be done. Therefore, at the time of frequency adjustment, the pad 51 and the like provided on the active surface are not exposed to ions or the like, and the IC chip 14 is not adversely affected.
Furthermore, the piezoelectric oscillator 54 can achieve the same effects as the piezoelectric oscillator according to the first embodiment.

  As a modification of the piezoelectric oscillator according to the third embodiment, a configuration as shown in FIG. That is, the piezoelectric oscillator 60 uses a package base 64 having a recessed portion 62 that is not provided with a step on its side surface. The piezoelectric vibrating reed 12 is mounted on the bottom of the recessed portion 62 and the IC chip 14 has an active surface upward. The IC chip 14 may be mounted on the upper surface of the package base 64 and the periphery of the IC chip 14 may be sealed with the molding material 56. At this time, the IC chip 14 may be electrically connected to the pad 51 provided on the active surface and the electrode 52 provided on the upper surface of the package base 64 by wire bonding.

Next, a fourth embodiment will be described. In the fourth embodiment, modifications of the sealing holes shown in the first to third embodiments will be described. FIG. 8 is a cross-sectional view showing a modification of the sealing hole.
The sealing hole 70 (70a, 70b) according to the fourth embodiment has a two-stage structure, and the diameter of the sealing hole 70a provided inside the package base is the diameter of the sealing hole 70b provided outside. Smaller than that. That is, the sealing hole 70 has a structure in which, for example, two insulating sheets are laminated on the bottom surface of the package base, the center position of the sealing hole 70 is set to the same position, and the insulating sheet positioned on the inner side of the package base and the outer side thereof. What is necessary is just to provide and provide the hole of a different diameter in the insulating sheet located. A conductive film 74 is provided on the bottom 72 of the sealing hole 70b outside the package base and part of the side surface of the sealing hole 70a inside the package base. Thereby, when the sealing material 40 is melted, the melted sealing material 40 adheres to the conductive film 74 and the sealing effect can be improved. Further, the conductive film 74 formed on the side surface of the sealing hole 70a inside the package base can prevent the molten sealing material 40 from reaching the inside of the package base. The sealing material 40 has a size larger than the hole diameter of the sealing hole 70a on the inner side of the package base and smaller than the hole diameter of the sealing hole 70b on the outer side of the package base. What is necessary is just to set it as the size which does not leak from the sealing hole 70b.

  Next, a fifth embodiment will be described. In the fifth embodiment, an example in which the piezoelectric oscillator described above is mounted on an electronic device will be described. FIG. 9 is a schematic configuration diagram of a digital mobile phone. The digital cellular phone 100 includes a transmission / reception signal transmission unit 102, a reception unit 104, and the like, and a central processing unit (CPU) 106 that controls them is connected to the transmission unit 102 and the reception unit 104. In addition to modulation and demodulation of transmission / reception signals, the CPU 106 controls the information input / output unit 108 including a display unit and operation keys for inputting information, and the memory 110 including RAM, ROM, and the like. For this reason, the piezoelectric device 112 is attached to the CPU 106, and its output frequency is used as a clock signal suitable for the control contents by a predetermined frequency dividing circuit (not shown) incorporated in the CPU 106. The CPU 106 is connected to a temperature compensated piezoelectric oscillator 114, and the temperature compensated piezoelectric oscillator 114 is connected to the transmitting unit 102 and the receiving unit 104. Thus, even if the basic clock from the CPU 106 fluctuates when the environmental temperature changes, it is corrected by the temperature compensated piezoelectric oscillator 114 and supplied to the transmitting unit 102 and the receiving unit 104.

  For example, there is a temperature compensated piezoelectric oscillator 114 to which the piezoelectric oscillator of the above-described embodiment is applied. The piezoelectric oscillator of the above-described embodiment can also be applied to a real-time clock that supplies date and time information to a mobile phone including the CPU 106, for example.

It is explanatory drawing of the piezoelectric oscillator which concerns on 1st Embodiment. It is explanatory drawing of hole sealing. It is explanatory drawing of the oscillation frequency distribution after the assembly of a piezoelectric oscillator. It is a modification of the piezoelectric oscillator which concerns on 1st Embodiment. It is sectional drawing of the piezoelectric oscillator which concerns on 2nd Embodiment. It is sectional drawing of the piezoelectric oscillator which concerns on 3rd Embodiment. It is a modification of the piezoelectric oscillator which concerns on 3rd Embodiment. It is sectional drawing which shows the modification of a sealing hole. It is a schematic block diagram of a digital mobile phone. It is a graph showing the relationship between the oscillation frequency f of the capacitance C _L and the piezoelectric oscillator of the capacitor array provided on the IC chip.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ......... Piezoelectric oscillator, 12 ......... Piezoelectric vibrating piece, 14 ......... IC chip, 20 ......... Depression, 24 ......... Sealing hole, 26 ......... Step, 34 ...... Excitation electrode, 40: Sealing material, 56: Mold material.

Claims (7)

Mounting the piezoelectric vibrating piece on the bottom of the package base;
Mounting a circuit for oscillating the piezoelectric vibrating piece above the piezoelectric vibrating piece in the package base;
Sealing the top of the circuit;
Adjusting the frequency of the piezoelectric vibrating piece through a hole provided in the bottom surface of the package base;
Sealing the hole;
A method for adjusting the frequency of a piezoelectric oscillator, comprising:   The method for adjusting a frequency of a piezoelectric oscillator according to claim 1, wherein the step of sealing the circuit is a step of bonding a lid to the upper surface of the package base.   The method for adjusting a frequency of a piezoelectric oscillator according to claim 1, wherein the step of sealing the circuit is a step of sealing an upper portion of the circuit with a molding material. A piezoelectric vibrating piece and an IC chip that oscillates the piezoelectric vibrating piece and is larger than the piezoelectric vibrating piece;
The piezoelectric vibrating piece is mounted on the bottom of the package with the excitation electrode provided on the piezoelectric vibrating piece facing the hole provided on the bottom of the package for frequency adjustment and airtight sealing,
The IC chip is provided above the piezoelectric vibrating piece.
A piezoelectric oscillator characterized by that.   The piezoelectric oscillator according to claim 4, wherein the IC chip is mounted on the package while hermetically sealing the piezoelectric vibrating piece.   The piezoelectric oscillator according to claim 5, wherein the IC chip is sealed with a molding material.   An electronic apparatus comprising the piezoelectric oscillator according to claim 4.

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