JP3398331B2 - Manufacturing method of temperature compensated crystal oscillator - Google Patents

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 a temperature-compensated crystal oscillator used in mobile communication equipment and the like.

[0002]

2. Description of the Related Art A crystal oscillator is a very important component for generating a reference frequency for controlling transmission / reception in mobile communication equipment. The crystal oscillator used for such a mobile communication device or the like has to be very small in volume as the mobile communication device is miniaturized.

In addition, the frequency must be stabilized even when used in an environment where the ambient temperature fluctuates drastically.

Therefore, in response to the requirements described later, the intrinsic temperature-frequency characteristic of the crystal unit (for example, in the case of the AT-cut thickness-slip crystal unit, the temperature-frequency characteristic represented by a cubic curve) is set. , Temperature compensation is performed to flatten the frequency with respect to the ambient temperature.

In order to perform this temperature compensation in a small size and with high performance, an oscillation inverter, at least a memory function for storing temperature compensation data for a predetermined temperature, a voltage conversion function, a varicap diode function, and a control function are integrated. Using an integrated IC chip, the oscillation frequency of the crystal unit, which fluctuates with respect to the ambient temperature, is set to a predetermined value for the capacitance value of the varicap diode that operates based on the temperature compensation data. The oscillation frequency as a whole was flattened.

As a temperature-compensated crystal oscillator that achieves such miniaturization and highly accurate temperature compensation, Japanese Patent Laid-Open No. 10-
A temperature-compensated crystal oscillator as shown in No. 28024 has been proposed. This temperature-compensated crystal oscillator uses a container body having a rectangular frame-shaped leg portion with an opening shape on the bottom surface of a single plate-shaped substrate, and having a rectangular cavity portion with an opening on the bottom surface. It was Then, a crystal oscillator is mounted on the surface of the container body, and a control circuit is mounted in the cavity of the container body.

7 to 9 are views showing the conventional temperature-compensated crystal oscillator.

The conventional temperature-compensated crystal oscillator has a container 5
1, a rectangular crystal oscillator 52, an IC chip 53 that constitutes an oscillation control circuit, and a metal lid 54.

In this temperature-compensated crystal oscillator, a frame-shaped leg portion 56 having a rectangular opening formed around the bottom surface of the single-plate ceramic substrate 55 is integrally formed on the single-plate ceramic substrate 55. The container 51 was used. As a result, the cavity 57 is formed on the bottom surface of the container body 51.

A single plate-shaped ceramic substrate 55 for partitioning the surface of the container 51 and the bottom of the cavity 57 has a via-hole conductor 58 for electrically connecting the front side with the cavity 57.
Is formed, and a sealing conductor pattern 59 for sealing the metallic lid 54 is formed on the surface thereof. A predetermined wiring pattern 60 including an IC electrode pad is formed on the bottom surface of the cavity 57. further,
Two external terminal electrodes 61 to 64 are formed on, for example, a pair of long side edges of the bottom surface of the frame-shaped leg portion 56. In addition, a plurality of recesses extending to the bottom surface are formed on the pair of short side end faces of the container body 1, and temperature compensation data writing terminal electrodes 65 to 68 are formed on the inner wall surfaces of the recesses.

Then, a strip-shaped crystal oscillator 52 is provided on the surface side of the container body 1 via crystal oscillator support bases 69 and 70.
Are conductively joined by conductive adhesives 71 and 72, and further, a substantially dish-shaped metal lid 54 is integrally formed by using a sealing conductor pattern 59 for hermetically sealing the crystal unit 52. Was joined to.

An IC chip 53 is mounted on the cavity 57. This IC chip 53 is an IC
It is connected to the electrode pad via a bump or a bonding wire. Further, a filling resin 73 is filled and hardened in the cavity 57. This allows the IC
The chip 53 is completely covered to improve the moisture resistance.

In the structure described above, the crystal oscillator 52 mounted on the surface of the container body 51 has via-hole conductors 58, 58.
Is connected to the IC chip 53 via an external terminal electrode 61 via a predetermined wiring pattern 60 ...
.., 64, and temperature compensation data writing terminal electrodes 65 to 68.

In the above temperature-compensated crystal oscillator, write terminal electrodes 65 to 68 for writing in the IC chip 53.
Are formed on a pair of side surfaces of the container body 51. However, actually, the write terminal electrodes 65 to 68 are formed from the side surface to the bottom surface of the container body 51.

The crystal oscillator having such a structure is manufactured by the following steps.

First, the container 51, the crystal oscillator 52, the IC
A chip 53 or the like is prepared.

Next, the supports 69, 7 on the surface of the container 51
The crystal unit 52 is mounted on the substrate 0, and the crystal unit 52 is hermetically sealed by the metal lid 54. For example, a seal ring is provided around the upper surface of the container body 51 in advance, the metal lid body 54 is placed, and seam bonding is performed.

Next, the IC chip 53 is mounted in the lower cavity 57 of the container 51. Specifically, I
The C chip 53 is bonded to the bottom surface of the cavity 57,
The IC chip 53 and the predetermined wiring pattern 60 including the IC electrode pad are bonded and connected via an Au wire.

Next, the filling resin 7 is filled in the cavity 57.
Fill 3 and cure.

After that, the predetermined temperature compensation data is written in the IC chip 53 by using the writing terminal electrodes 65 to 68 which are led out to the outer surface of the container body 51.

[0021]

In the above temperature-compensated crystal oscillator, the crystal oscillator 52 and the IC chip 53 are separated by the ceramic substrate 55 of the container body 51, and they are separately mounted. ing.

However, if the oscillation characteristics of the previously mounted crystal unit 52 have characteristics that cannot be controlled by the temperature compensation circuit, or if there is an oscillation failure, the inside of the cavity 57 on the bottom surface of the container body 51 will be described. The defective state of the crystal oscillator 52 can be discriminated only after the IC chip 53 is mounted on and the measurement is performed using the external terminal electrodes 61 to 64.

Therefore, if the crystal unit 52 is defective, the crystal unit 52 and the crystal unit 52 mounted on the container body 51
Each C chip 53 had to be discarded, which was very costly.

It is also conceivable that after mounting the crystal unit 52 on the container 51, monitor electrode pads for measuring the oscillation characteristics of the crystal unit 52 are formed on the outer surface of the container 51. . However, in the final temperature-compensated crystal oscillator, if the monitor electrode pad is exposed on the outer surface of the container body 51 after being mounted on the printed wiring board, unnecessary electric noise from the outside is not added. There is a problem that it has to be processed as follows.

The present invention has been devised in view of the above-mentioned problems, and an object thereof is to be able to measure the characteristics of a crystal resonator mounted in a container and to achieve stable predetermined oscillation. The present invention provides a method for manufacturing a temperature-compensated crystal oscillator that is small in size without waste of the IC chip and that enables stable operation of the IC chip.

[0026]

According to a first aspect of the present invention, a lower surface has a cavity portion, an upper surface is provided with an electrode pad on which a crystal oscillator is mounted, and an inner surface of the cavity portion is provided with a monitor electrode pad. Preparing a container body, mounting a crystal resonator on the upper surface of the container body, connecting the crystal resonator to the monitor electrode pad, and using the monitor electrode pad A step of adjusting the oscillation characteristic as necessary while measuring the oscillation characteristic, a step of thermally aging the crystal resonator, and a step of covering a lid body that hermetically seals the crystal resonator with a lid body. A temperature-compensated crystal oscillator, comprising: a step of accommodating an IC chip in the cavity portion; and a step of writing temperature compensation data for temperature compensation of the crystal resonator in the IC chip. It is a production method.

Preferably, the temperature compensation type crystal oscillator is formed on the side surface of the container body, which is connected to an IC chip and has an IC control terminal electrode for writing temperature compensation data.

[0028]

In the present invention, the crystal oscillator is mounted on the upper surface side of the container body having the cavity portion formed on the lower surface, and the IC chip is mounted in the cavity portion. That is, since the crystal unit and the IC chip are arranged in the thickness direction of the container body, the size of the temperature compensated crystal oscillator can be reduced, which can reduce the mounting area on the printed wiring board.

Moreover, since the crystal unit and the IC chip are separately arranged in different storage areas, the crystal unit can be maintained in a stable storage environment for a long period of time.
It is possible to stabilize the oscillation operation of the crystal unit.

A monitor electrode pad for measuring the oscillation characteristics of the crystal unit mounted on the upper surface of the container is formed on the inner surface of the cavity. Therefore, since the monitor electrode pad is not exposed on the outer surface of the container body, unnecessary electrical noise or electric shock from the outside is not applied after the temperature-compensated crystal oscillator is mounted on the printed wiring board. The stable operation of the crystal unit can be maintained.

Further, it is possible to measure the oscillation characteristics of the crystal oscillator alone mounted on the container body using the monitor electrode pad before mounting the IC chip. Thus, the oscillation characteristics of the crystal unit can be easily measured and adjusted before mounting the IC chip, and can be easily compensated by the temperature compensation data.

In mounting the crystal unit, a thermal aging process is performed to stabilize the adjusted frequency, but this thermal aging process can be performed before mounting the IC chip. As a result, since there is no unnecessary heat application to the IC chip due to the heat aging process, stable operation of the IC chip becomes possible.

Further, even if the crystal unit is forced to be discarded due to a defect in the crystal unit, the IC chip is in an unmounted state, so that it is necessary to waste the IC chip and to carry out a wasteful manufacturing process thereafter. Disappears.

In the manufacturing method, first, a crystal oscillator is mounted on the upper surface of the container, the frequency of the crystal oscillator is adjusted, and a thermal aging process for frequency stabilization is performed. And
After sealing the crystal unit, the IC chip is mounted in the cavity for the first time.

That is, since the IC chip is mounted after the heat treatment process necessary for mounting the crystal unit is completed, I
The number of thermal histories applied to the C chip can be reduced.

Therefore, the operational reliability of the IC chip can be improved. At the same time, it is possible to effectively suppress the Cargendhal void phenomenon that occurs at the bonding surface between the electrode of the IC chip and the connection member (bump or wire).
The bonding state of the IC chip is also stable, which also helps
It enables stable operation of the chip.

[0037]

BEST MODE FOR CARRYING OUT THE INVENTION A method of manufacturing a temperature-compensated crystal oscillator of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a sectional view of a temperature-compensated crystal oscillator according to the present invention, FIG. 2 is a side view, FIG. 3 is a top view with a lid omitted, and FIG. It is a bottom view of the omitted state. FIG. 5 is a schematic plan view showing an internal wiring pattern. Note that FIG. 1 shows a cross section taken along line XX of FIG.

The temperature-compensated crystal oscillator according to the present invention is
A substantially rectangular parallelepiped container body 1 having a flat upper surface (hereinafter referred to as the front surface) and a concave cavity portion formed on the lower surface (hereinafter referred to as the bottom surface) side, a rectangular crystal resonator 2, and a control circuit are configured. IC chip 3 and two electronic component elements 4,
5, a metal lid 6 and a filling resin 7 are mainly included.

The container body 1 is constructed by integrally laminating a plurality of substantially rectangular ceramic insulating layers 1a and 1b and generally frame-shaped ceramic insulating layers 1c and 1d having openings of different shapes. The ceramic insulating layers 1a and 1b serve as partitions 8 for partitioning the crystal unit 2 from the IC chip 3 and the electronic component elements 4 and 5, and also the ceramic insulating layers 1c and 1b.
The frame-shaped leg portion 9 is formed by d. With this frame-shaped leg portion 9, a concave cavity portion 10 surrounded by the bottom surface and the frame-shaped leg portion 9 is formed on the bottom surface of the partition portion 8.

External terminal electrodes 11 to 14 are formed at four corners of the bottom surface of the container body 1, respectively. Further, a plurality of IC control terminal electrodes 15 to 18 for writing temperature compensation data necessary for the IC chip 3 and various information for control are formed on the pair of long side surfaces of the container body 1.

On the surface of the container body 1, that is, the surface of the partition portion 8, the sealing conductor pattern 19 is formed so as to surround the outer periphery thereof.
Further, crystal oscillator electrode pads 20 and 21 for connecting to the crystal oscillator 2 are juxtaposed near one end of the surface of the container body 1 in the longitudinal direction. Further, the crystal unit 2 is provided on the crystal unit electrode pads 20 and 21 described above.
The connection bumps 22 and 23 for forming a predetermined space between the surface of the container body 1 and the container body 1 are formed. In the present invention, the electrode bumps including the connection bumps 22 and 23 are mounted on the crystal resonator 2.

A holding bump 24 for supporting the other end of the crystal unit 2 is formed near the other end of the surface of the container body 1 in the longitudinal direction.

Further, two via-hole conductors 25 and 26 (note that 26 is omitted in the figure) connected to the crystal oscillator electrode pads 20 and 21 are formed in the ceramic insulating layer 1a, and the ceramic insulating layer 1b is formed. Is the cavity 10
Second via-hole conductors 27, 28 extending to the bottom surface of the via-hole conductors 25, 27, 26, 28 are formed between the ceramic insulating layers 1a, 1b. Are formed.

On the bottom-side main surface of the ceramic insulating layer 1b, the IC chip 3 and the above-mentioned IC control terminal electrodes 15 to 1 are provided.
8 and the IC chip 3 and the electronic component element 4,
5, the IC chip 3, the electronic component element 4,
5 and various wiring patterns 31 ... Which are connected to the external terminal electrodes 11 to 14 are formed. The cavity 1
, Which form a part of various wiring patterns 31 in the bottom area of 0, element electrode pads 33, ...
Are formed. The second via-hole conductors 27, 2
8 is an IC directly or through a predetermined wiring pattern 31
Although connected to the input electrodes of the chip 3, at the same time, monitor electrode pads 34 and 35 are formed on the bottom surface of the cavity portion 10.

As described above, inside the container body 1, one end is a surface and the other end is led out into the cavity portion 10. The via hole conductor 25, the internal wiring pattern 29, the via hole conductor 27, and the via hole conductor 26. A conductive path including the internal wiring pattern 30 and the via-hole conductor 28 is formed.

Regarding the structure of the external terminal electrodes 11 to 14, the flat surface portions 11a formed at the four corners of the bottom surface of the container body 1 are used.
.About.14a, and four end portions 11b to 14b formed on the inner wall of a recess having a cutout of approximately 1/4 circular shape in the thickness direction at four corners of the ceramic insulating layers 1c and 1d. In addition, the external terminal electrode 13 having the ground potential is connected to the sealing conductor pattern 19 formed on the surface of the container body 1,
The metal lid 6 is made to achieve the shield effect. Therefore, as for the external terminal electrode 13 having the ground potential, as shown in the drawing, the via hole conductor and the wiring pattern penetrating all of the ceramic insulating layers 1a to 1d are connected to the sealing conductor pattern 19 or the external terminal electrode is used. The end surface portion 13 b of 13 extends to the surface of the container body 1 and is connected to the sealing conductor pattern 19.

Further, the IC control terminal electrodes 15 to 18 are not formed on the ceramic insulating layers 1a and 1d, but an intermediate layer sandwiched between the ceramic insulating layers 1a and 1d, for example, ceramic insulating layers 1b and 1c. It is formed on the end face of the long side. Therefore, as shown in FIG. 2, the IC control terminal electrode 1
5 to 18 (15 and 16 in FIG. 2) are formed on the side surface of the container body 1 without contacting the bottom surface and the surface.
This avoids a short circuit with the sealing conductor pattern 19 formed on the front surface side of the container body 1, and when the bottom surface side of the container body 1 is soldered to a printed wiring board, a printed wiring board is formed. This is to avoid a short circuit with the wiring pattern on the board. Furthermore, the IC control terminal electrodes 15-18 are
It is preferable that the ceramic insulating layers 1b and 1c have a concave portion formed on the end surface on the long side and are formed on the inner wall surface of the concave portion. As a result, an external factor, for example, a carrying means for carrying the temperature-compensated crystal oscillator onto the printed wiring board comes into contact with the IC control terminal electrodes 15 to 18, and the temperature compensation data written in the IC chip 3 fluctuates. However, the temperature compensation operation is prevented from malfunctioning.

The above-mentioned container body 1 has a ceramic insulating layer 1a.
It is formed by using a ceramic green sheet of 1 to 1d. Specifically, for example, through holes to be the first via hole conductors 25 and 26 are formed in the rectangular ceramic green sheet to be the insulating layer 1a, and the through holes are filled with a high melting point metal paste such as molybdenum or tungsten. At the same time, a conductor film to be the crystal oscillator electrode pads 20 and 21, a conductor film to be the bumps 22 to 24, and a sealing conductor pattern 19 are formed on the surface.
The conductor film to be formed is formed by printing the above-mentioned conductive paste.

In addition, the rectangular ceramic green sheet serving as the insulating layer 1b is formed with the through holes serving as the second via-hole conductors 27 and 28 and the recessed portion in which the IC control terminal electrodes 15 to 18 are formed. The through hole is filled with paste, and a conductor film is formed on the inner wall surface of the recess. At the same time, the IC electrode pad 32, the element electrode pad 33, and
Monitor electrode pads 34, 35 and IC electrode pads 32,
A conductor film is formed which connects the element electrode pad 33 and each of the terminal electrodes 11 to 18 and becomes various wiring patterns 31 forming a predetermined circuit network.

In addition, either the green sheet to be the ceramic insulating layer 1a or the ceramic insulating layer 1b is connected to the inside thereof to connect the first via-hole conductors 25, 26 and the second via-hole conductors 27, 28 to the joint surface. The conductor film to be the wiring patterns 29 and 30 is formed by printing the above-mentioned high melting point metal paste.

Further, the frame-shaped ceramic green sheet having the irregular shaped opening which becomes the ceramic insulating layer 1c is formed with the concave portions which become the end face portions 11b to 14b of the external terminal electrodes and the IC control terminal electrodes 15 to 18, and On the inner wall surface of the recessed portion, a conductor film to be the end surface portions 11b to 14b of the external terminal electrodes and the IC control terminal electrodes 15 to 18 is formed with the above-mentioned high melting point metal paste.

Further, the frame-shaped ceramic green sheet having the irregular shaped opening which becomes the ceramic insulating layer 1d is formed with the concave portions which become the end face portions 11b to 14b of the external terminal electrodes 11 to 14 and the inner wall surface of the concave portion. The end face portions 11b to 1 of the external terminal electrodes 11 to 14 are made of the above-mentioned high melting point metal paste.
A conductor film to be 4b is formed. At the same time, conductor films to be the flat surface portions 11a to 14a of the substantially rectangular external terminal electrodes 11 to 14 are formed at the four corners of the bottom surface of the green sheet. In addition, the substantially rectangular flat surface portions 11a to 14a are 4
It is formed so as to extend so as to be electrically connected to the end surface portions 11b to 14b formed in the recessed portions of the one corner.

Next, after laminating and press-bonding each green sheet as described above, a firing process is performed. In particular, since the crystal unit 2 is mounted on the surface of the container body 1 and the IC chip 3 is mounted on the cavity portion 10, the flatness of both surfaces is important. In the pressure-bonding step, pressing is performed with the surface of the container body 1 as a reference surface, but in order to perform pressing with uniform pressure on the bottom surface region of the cavity portion 10, for example, the cavity portion 10 is also used.
Is filled with an auxiliary filling member, or the upper punch having a flat pressing tip surface is pressed with a convex jig, or the ceramic insulating layers 1a and 1b and the ceramic insulating layers 1c and 1d are separately pressed. After that, both are crimped by a press.

Next, the external terminal electrodes 11 to 14 exposed on the surface of the container body 1, the IC control terminal electrodes 15 to 18, the sealing conductor pattern 19, the crystal oscillator electrode pads 20 and 2.
1, IC electrode pad 32 ..., Element electrode pad 33.
The container body 1 is achieved by applying Ni plating, flash gold plating, or the like on the monitor electrode pads 34, 35, various wiring patterns 31, and bumps 22 to 24.

As a result, the via-hole conductors 25 to 28 and the wiring patterns 29 and 31 formed inside the container body 1 are formed.
Is made of a refractory metal conductor such as molybdenum or tungsten, and is exposed on the surface of the container body 1 to the electrodes 11 to 1.
8, sealing conductor pattern 19, each electrode pad 20, 2
1, 32, ..., 33 ,, monitor electrode pads 34,
35 and various wiring patterns 31 have a multilayer structure of a Ni layer and a gold layer on the refractory metal conductor.

The external terminal electrode 13 having the ground potential
Depending on the connection structure between the sealing conductor pattern 19 and the sealing conductor pattern 19, for example, a via-hole conductor and an internal wiring pattern penetrating the ceramic insulating layers 1a to 1d may be simultaneously formed at the time of forming the via-hole conductor and the wiring pattern described above, or, for example, ceramic. Even at only one corner of the insulating layers 1a and 1b,
The recess may be formed and the conductor film may be formed to extend the end surface portion 13b. This is not limited to the ground potential, for example, a terminal electrode of VCC through which a large current can flow,
In connection with the wiring pattern 31, the via-hole conductors may be formed not only in one corner of the ceramic insulating layers 1c and 1d but also in the frame-shaped leg 9 so as to be connected to each other.

On the surface of the container body 1, the connection bumps 22, 2 are formed on the crystal oscillator electrode pads 20, 21.
3. The holding bumps 24 were formed on the other end side by overlapping printing of the conductive paste. The holding bumps 24 were formed by applying / baking a conductive paste containing Ag powder or applying / curing a resin paste containing Ag powder. May be. Further, the connection bumps 22 and 23 may be applied a plurality of times in order to have a predetermined height. Preferably, the height from the surface of the container body 1 to the tops of the connection bumps 22 and 23 is, for example, 15
The height to the apex of the holding bump 24 is, for example, 5 to 10 than that of the connecting bumps 22 and 23.
It is a low value of about μm.

Further, a seal ring 36, which is a substantially rectangular metal frame, is bonded onto the sealing conductor pattern 19. The seal ring 36 is made of 42 alloy, Kovar, phosphor bronze, or the like and has a structure corresponding to the shape of the sealing conductor pattern 19. The seal ring 36 is joined to the sealing conductor pattern 19 by brazing.

The crystal unit 2 is arranged on the surface of the container body 1 as described above. The crystal resonator 2 includes vibrating electrodes 2b and 2c formed on both main surfaces of a rectangular crystal plate 2a which is cut in a predetermined manner, for example, AT cut, the vibrating electrodes 2b,
2c, an island-shaped lead-out electrode portion 2 extending from one side to the other end
d, 2e. In addition, in FIG. 3, the vibration electrode 2c and the extraction electrode 2e on the lower surface side are indicated by dotted lines. The extraction electrodes 2d, 2e are the crystal oscillator electrode pads 20,
21 and the conductive adhesives 2f and 2g.

Further, the vibrating electrodes 2b and 2c and the extraction electrode 2
d and 2e are Cr or N as a base on both sides of the crystal plate 2a.
i, vapor deposition of a conductive material such as Ag or Au as a surface layer,
It is deposited by a thin film technique such as sputtering.

The crystal resonator 2 mounted on the front surface side of the container body 1 is hermetically sealed by the metal lid body 6. The metal lid 6 is made of a metal material such as Kovar or 42 alloy, has a thickness of, for example, 0.1 mm, and is a frame-shaped seal ring 36 brazed to the sealing conductor pattern 19 on the surface of the container 1. Welded and joined so as to be in close contact with.
In addition, Ni, aluminum, or the like is adhered to the outer main surface of the metallic lid 6. This prevents the brazing filler metal from melting during welding and wraps around the main surface side, ensuring stable and strong welding.
It enables them to be joined.

On the bottom surface of the cavity portion 10 of the container body 1, an IC chip 3 constituting a control circuit for controlling oscillation is mounted. The IC chip 3 controls and oscillates and outputs the frequency variation of the crystal resonator 2 due to the characteristic temperature-frequency characteristic indicated by, for example, a cubic curve so as to be flattened in a wide temperature range including normal temperature. Specifically, by well-known PN doping on a silicon chip, in addition to an oscillating inverter, a load capacitance component, and a feedback resistor that form an oscillating circuit, temperature compensation necessary for flattening the intrinsic temperature frequency characteristic of the crystal unit 2 is provided. A memory unit that stores data, a temperature sensor unit that detects the ambient temperature, a varicap diode, a DA conversion unit that converts a predetermined voltage based on predetermined temperature compensation data and supplies the varicap diode, and a signal that is written from the outside. It is composed of an AD conversion means held in the memory portion, a processor portion controlling these operations, and the like.

To such an IC chip 3, for example, a VCC terminal to which a power supply voltage is supplied and a G terminal which becomes a ground potential are provided.
An ND terminal, a crystal connection terminal connected to the crystal unit 2, an OUT terminal for oscillating output, a VCON terminal for enabling frequency adjustment from the outside, and, for example, four data write control terminals used for writing compensation data. Have

The VCC terminal (power supply section) of the IC chip 3 is
It is led out to the external terminal electrode 11 via a predetermined IC electrode pad 32 and a predetermined wiring pattern 31. Further, the OUT terminal has a predetermined IC electrode pad 32 and a predetermined wiring pattern 31.
Through the external terminal electrode 12.

The GND terminal (a kind of power supply section) is led out to the external terminal electrode 13 via the predetermined IC electrode pad 32 and the predetermined wiring pattern 31. The VCON terminal is led to the external terminal electrode 14 via the predetermined IC electrode pad 32 and the predetermined wiring pattern 31. In addition, the two crystal connection terminals include a predetermined IC pad 32 and a predetermined wiring pattern 3.
1, the monitor electrode 34 (35), the second via-hole conductor 2
Container body 1 via a conductive path formed by 7, 28, internal wiring patterns 29, 30, and first via-hole conductors 25, 26.
Are led out to the electrode pads 20 and 21 on the surface of, respectively.
Further, the four data write control terminals are respectively connected to the IC via a predetermined IC electrode pad 32 and a predetermined wiring pattern 31.
It is led to the control terminal electrodes 15 to 18.

Each of these terminals is formed as an aluminum electrode on the mounting surface of the IC chip 3, for example. It should be noted that bumps such as gold or solder are formed on each aluminum electrode, and the IC electrodes are bonded and connected to the above-mentioned IC electrode pads 32 ... By ultrasonic bonding or bonding using a conductive filler. Although each aluminum electrode may be formed on the upper surface side of the IC chip 6 and connected to the IC electrode pads 32, ... Through bonding wires, for example, care should be taken so that the shape of the cavity 10 does not become large. There is a need.

The electronic component elements 4 and 5 are, for example, chip capacitors. For example, the electronic component elements 4 and 5 are joined between the pair of element electrode pads 33 and 33 via a conductive resin adhesive containing Ag powder.

The capacitor which is the electronic component element 4 is an IC
Between the chip 3 and the external terminal electrode 12 serving as OUT, one is connected to have the ground potential. This is to remove the DC component that becomes noise in the output signal.

Further, the capacitor which is the electronic component element 5 is connected between the IC chip 3 and the external terminal electrode 11 which becomes VCC, and the high frequency noise superposed on the power supply voltage supplied to the external terminal electrode 11 which becomes VCC. Is to be removed.

Then, in the cavity portion 10, the IC chip 3 and the two electronic component elements 4 and 5 are arranged side by side in accordance with the shape of the cavity portion 10 so as to minimize the mounting space. ing.

For example, as shown in FIG. 4, for example, the plane shape is on the central axis of the width of the short side of the container body 1 of the IC chip 3,
Electronic component elements 4 and 5 having a small planar shape are arranged in parallel. That is, in the figure, the electronic component element 4, the IC chip 3, and the electronic component element 5 are arranged in this order, and the overall layout shape of the electronic component element 4, the IC chip 3, and the electronic component element 5 is a substantially cross shape.

In addition, the shape of the plane opening (bottom surface) of the cavity portion 10 is a substantially cross shape that is substantially similar to the overall arrangement structure of the electronic component element 4, the IC chip 3, and the electronic component element 5.

For example, the cavity portion 10 extends from the central portion 10e having a rectangular shape toward each side, and the cavity portion 10 has four portions.
Overhanging portions 10a to 10d extending between adjacent areas of the external terminal electrodes 11 to 14 formed at one corner are formed, and thus, the protrusions 10a to 10d have a substantially cross shape. The electronic component element 5 is mainly arranged in the overhang portion 10a, and the electronic component element 4 is mainly arranged in the overhang portion 10c. The IC chip 3 is arranged in the central portion 10e and the protruding portions 10b and 10d. That is, the cavity portion 10 has the external terminal electrode 11
.. to 14 are avoided, and in consideration of the arrangement shapes of the IC chip 3 and the electronic component elements 4 and 5 arranged in the cavity portion 10, the miniaturization is most achieved and the bonding strength of the external terminal electrodes 11 to 14 is maintained. It has a possible shape.

The cavity portion 10 has the above-mentioned I
A filling resin 7 is filled and formed in order to firmly bond the C chip 3 and the electronic component elements 4 and 5 and to improve the moisture resistance reliability. The filling resin 7 is, for example, at least 2
A resin layer 7a which is made of various kinds of filling resin, and which is mainly filled and cured on the bottom surface side of the cavity portion 10, and the resin layer 7
It is a resin layer 7b that is filled and cured on a. Specifically,
The cavity portion 10 is made of a resin material that has a relatively large shrinkage factor that is filled and cured on the bottom surface side. It is a material containing a large amount of resin components such as epoxy resin, which is generally called underfill resin. The resin layer 7a is filled and hardened so as to completely cover at least the upper surface of the IC chip 3.

That is, the IC chip 3, the electronic component elements 4, 5
The stress generated by the contraction of the resin layer 7a filled between the resin layer 7a and the bottom surface of the cavity portion 10 improves the bonding strength between the two. Moreover, the stress generated by the contraction of the resin layer 7a formed so as to completely cover the IC chip 3 is generated toward the IC chip 3. As a result, the stress acts to press the IC chip 3 from the upper surface side to the bottom surface side of the cavity portion 10, and the bonding strength of the IC chip 3 bonded to the bottom surface of the cavity portion 10 is improved.

Further, the resin layer 7b is made of the resin layer 7a having a large shrinkage stress, so that the IC chip 3 and the electronic component elements 4, 5,
The resin layer 7a for coating the resin is thinned, and as a result, the resin layer 7a is filled and cured in order to solve the problem that sufficient moisture resistance and the like cannot be obtained. This allows
The bonding strength of the IC chip 3 and the electronic component elements 4 and 5 mounted in the cavity portion 10 is improved, and the moisture resistance reliability is improved.

The filling resin 7 should not be projected from the opening surface of the cavity 10.

This is for stably disposing the temperature-compensated crystal oscillator on the printed wiring board.

In the present invention, the cavity portion 10 is formed on the bottom surface side of the container body 1, the crystal resonator 2 is mounted on the surface of the container body 1, and the cavity portion on the bottom surface of the container body 1 is mounted. An IC chip 3 is mounted on 10.
It should be noted that electronic component elements 4 and 5 are simultaneously disposed in the cavity portion 10.

That is, the crystal oscillator 2 is independently arranged in the airtight region surrounded by the surface of the container body 1, the seal ring 36 and the metal lid body 6, and the IC chip 3 is placed in the cavity of the container body 1. It is mounted in a region inside the unit 10 and both are arranged in completely different regions.

Therefore, since the operating environment of the crystal unit 2 does not change with time, stable operation of the crystal unit 2 can be achieved.

Further, since the crystal unit 2 and the IC chip 3 are laminated and arranged in the thickness direction of the device via the partition section 8 of the container body 1, the temperature compensation type crystal oscillator is mounted on the printed wiring board. The mounting area of is also small.

In addition, the first via-hole conductors 25, 2 are attached to the crystal unit 2 mounted inside the cavity 10.
6, internal wiring patterns 29, 30, and monitor electrode pads 34, 35 connected via the conductive paths of the second via-hole conductors 27, 28 are formed.

That is, the monitor electrode pads 34 and 35 are not exposed on the outer surface of the container 1. As a result, after the temperature-compensated crystal oscillator is bonded onto the printed wiring board, unnecessary electric noise, electric shock, stray capacitance, etc. from the outside are not applied, so that stable operation of the crystal resonator 2 can be maintained. . Moreover, as shown in FIG. 4 and FIG.
If the monitor electrode pads 34 and 35 are hidden by the C chip 3, the main body of the IC chip 3 is substantially set to the ground potential, so that the floating generated on the printed wiring board and the monitor electrode pads 34 and 35. Since the capacitance can be cut off, for example, no shield electrode is required on the outer surface of the filling resin 7, and the wiring pattern on the printed wiring board can be freely designed.

The oscillation characteristics of the crystal unit 2 mounted on the container body 1 using the monitor electrode pads 34 and 35 are
It can be measured before mounting the IC chip 3. This makes it easy to adjust the frequency fluctuation of the crystal unit 2,
Especially, the crystal unit 2 that can be easily compensated by the temperature compensation data
Oscillation characteristics of

Further, even if the entire container body 1 has to be discarded due to the oscillation failure of the crystal unit 2,
Since the IC chip 3 is not mounted on the container body 1,
The chip 3 is not wasted. As a result, the temperature-compensated crystal oscillator is inexpensive as a whole.

Further, regarding the operation of the IC chip 3, the thermal aging step is carried out in order to stabilize the adjusted frequency of the crystal resonator 2, but it is not necessary to mount the IC chip in this thermal aging step. This is because, as described above, the monitor electrode pads 34 and 35 for measuring the oscillation characteristics of the crystal unit 2 are extended inside the cavity 10. Therefore, since unnecessary heat application such as a heat aging process to the IC chip 3 is not performed, stable operation of the IC chip becomes possible.

Next, a method of assembling the above temperature-compensated crystal oscillator will be described with reference to the process chart of FIG.

First, the container body 1 which is the step (a) of FIG. 6 is formed. The detailed structure and the forming method thereof are as described above. The seal ring 36 may be joined to the surface of the container body 1 by brazing or the like.

At the same time, the step of selecting the crystal unit 2 which is the step (b) of FIG. 6 is performed. That is, the frequency characteristics of the crystal unit 2 change greatly due to a slight change in the cut angle. Therefore, the crystal oscillator capable of temperature compensation by the IC chip 3 and the rank classification due to the variation in frequency are performed.

Next, in step (c) of FIG. 6, a non-defective crystal oscillator 2 which is selected and satisfies the predetermined characteristics is mounted on the surface of the container 1. Specifically, the connection bumps 2 formed on the crystal oscillator electrode pads 20 and 21 on the surface of the container body 1
2, 23 and the extraction electrode portions 2d, 2e of the crystal unit 2 are positioned and placed so as to match with each other, and the extraction electrode portions 2d, 2e are placed.
And the electrode pads 20 and 21 with a conductive adhesive material 2 such as Ag.
Both are joined using f and 2g. The lower surface on the other end side of the crystal resonator 5 is placed on the holding bumps 24 for bonding, and at this time, a contraction stress acts when the conductive adhesive material is cured, and the crystal resonator 2 is A gap corresponding to the height of the connection bumps 22 and 23 is formed between the surface of the container body 1 and the other end side.

As a result, the vibrating electrode 2 of the crystal unit 2 is
b and 2c are the electrode pads 20 and 21, the first via hole conductors 25 and 26, the internal wiring patterns 29 and 30, and the second.
The cavity portion 1 is provided via the via-hole conductors 27 and 28.
It is led out to the predetermined wiring pattern 31 and the monitor electrode pads 34 and 35 formed on the bottom surface of 0.

Next, the frequency of the crystal resonator 2 is measured in step (d) of FIG. Specifically, the measuring electrode (probe) of the frequency measuring device is brought into contact with the monitor electrode pads 34 and 35 formed on the bottom surface of the cavity portion 10,
The crystal oscillator 2 is oscillated in a predetermined manner and the frequency is measured.

Next, the frequency of the crystal resonator 2 is adjusted in the step (e) of FIG. Specifically, Ag on the vibrating electrode 2b on the upper surface side of the crystal unit 2 bonded to the container body 1
A metal such as is vapor-deposited, and the oscillation frequency is adjusted by substantially varying the mass of the vibrating electrode 2b. At this time, adjust the frequency so that the IC chip 3 can easily perform temperature compensation.
For example, the frequency at room temperature is set to the required frequency. This improves the reliability of the temperature compensation operation of the IC chip 3. Further, the amount of information of the compensation data is very small, and the memory section for storing this data has a small capacity, which is advantageous for downsizing and low cost of the IC chip 3.

Depending on the structure of the vapor deposition apparatus, the measurement of the frequency of the crystal unit 2 in the step (d) of FIG. 6 and the adjustment of the frequency of the crystal unit 2 in the step (e) can be simultaneously performed. .

Next, the frequency characteristic of the crystal resonator 2 is stabilized in step (f) of FIG. Specifically, the entire container body 1 to which the crystal unit 2 is bonded is heat-treated at 150 to 250 ° C. This heat treatment is generally called heat aging.
This thermal aging stabilizes the deposited material for frequency adjustment deposited on the vibrating electrode 2b. This stabilizes the frequency characteristic of the crystal unit 2. Further, impurities such as a solvent contained in a conductive paste or the like for joining the crystal unit 2 are volatilized. This is to prevent the environment containing the crystal unit 2 from changing with time,
The predetermined oscillation operation of the crystal resonator 2 can be stabilized for a long period of time.

This step is performed before the metal lid 6 is covered. This is because impurities are completely volatilized from the storage area of the crystal unit 2 to the outside. Also, IC
It is performed before the chip 3 is mounted in the cavity portion 10. This is to reduce the number of times of heat application, which is a cause of lowering the operational reliability of the IC chip 3. As a result, the operation reliability of the IC chip 3 is also improved at the same time.

Next, the crystal resonator 2 is covered with the metallic lid 6 in the step (g) of FIG.

Specifically, the metal lid 6 is placed on the seal ring 36 provided around the surface of the container body 1, and the periphery of the metal lid 6 is covered with a roller electrode for seam welding (not shown). No)
Then, the two are welded by moving while applying a welding current. At this time, the accommodation area of the crystal unit 2 surrounded by the surface of the container body 1, the seal ring 36, and the metal lid body 6 is set to have a predetermined atmosphere. Moreover, after that, the thermal aging process is performed again as needed. This is because it is conceivable that impurities and the like in the accommodation area will invade from the previous thermal aging step to this step, and such impurities and the like are attached and fixed to the inner surface of the metal lid body 6 and accommodated. This is for keeping the area in a predetermined atmosphere.

After this step is completed, the final oscillation characteristics of the crystal unit 2 housed in the hermetically sealed area are monitored by the monitor electrode pad 3 formed on the bottom surface of the cavity 10.
It is desirable to measure at 4 and 35. This is because the temperature compensation data in the final process is used as a basis for determining the data to be written.

Next, the pretreatment of the IC chip 3 which is the step of FIG. 6H is performed. This pretreatment can be omitted depending on the method of joining the IC chips 3. In this embodiment, since the IC chip 3 is bonded to the IC electrode pads 32 ... On the bottom surface of the cavity portion 10 via the bump, the bump is formed in this step. For example, Au bumps are formed using an Au wire or the like on the aluminum electrodes of each input / output unit on the mounting surface of the IC chip 3.

When high heat is applied with the Au bumps formed on the aluminum electrodes, the Cargendard void phenomenon occurs due to the difference in the diffusion speed of Al and Au, and the connection at the bonding interface between Al and Au is generated. Although the strength decreases, such a problem does not occur because the heat aging step or the heat aging treatment has already been completed as in the above technique.

Next, the IC chip 3 which is the step (i) in FIG. 6 is mounted in the cavity portion 10. At the same time, the electronic component elements 4 and 5 are also mounted.

The IC chip 3 is mounted by positioning the IC chip 3 so that the Au bumps formed on the IC chip 3 and the IC electrode pads 32. Ultrasonic waves or the like are applied to fuse them.

Further, the electronic component elements 4 and 5 are joined by applying a conductive resin paste containing Ag powder or the like to the element electrode pads 33, ... The resin paste is cured and cured.

If it is not desired to apply the heat during the curing process to the IC chip 3, the IC chip 3 may be mounted after mounting the electronic component elements 4 and 5.

Next, the filling resin 7 is filled and cured in the cavity 10 which is the step (j) of FIG.

Specifically, the entire IC chip 3 and electronic component elements 4, 5 are completely covered with a resin material generally called underfill to be cured to form a resin layer 7a, and subsequently, a resin layer 7a is formed on the resin layer 7a. The resin layer 7b is formed by filling and curing an epoxy resin having excellent moisture resistance.

By this step, the bonding strength, which is only about 60 g per bump, is dramatically improved by forming the underfill so as to cover the upper surface of the IC chip 3 in particular.

Next, the step of writing data to the IC chip 3, which is the step (k) of FIG. 6C.

The data to be written are data for flattening the oscillation frequency in a wide temperature range including normal temperature in accordance with the frequency characteristics of the crystal unit 2 mounted on the surface of the container 1, and if necessary, this It is data such as a program for processing the data.

Specifically, for example, a probe of a memory writer device is brought into contact with the IC control terminal electrodes 15 to 18 formed on the inner wall of the recess on the side surface of the container body 1 to write predetermined data.

If necessary, based on the compensation data stored by writing, the frequency compensation state due to the temperature change is confirmed, and if the compensation is necessary again, the compensation compensation data may be written.

The data to be written differs depending on the temperature compensation operation. For example, the data for correcting the oscillation frequency of the crystal unit 2 at a predetermined temperature by the operation control of the varicap diode according to the variation amount from the reference frequency. Is. That is, it is data for optimizing the voltage for controlling the capacitance of the varicap diode in order to correct the frequency displacement amount based on the ambient temperature by the temperature sensing means. As a result, the inherent temperature-frequency characteristic of the crystal unit 2 is flattened in a wide temperature range including normal temperature.

In the manufacturing method described above, the crystal unit 2 is mounted in the step (a) of FIG. 6, and the frequency of the crystal unit 2 is measured and adjusted in the steps (c) to (f) of FIG. Furthermore, a heat aging process for frequency stabilization is performed. Then, after sealing the crystal resonator 2 in the step of FIG. 6G, the IC chip 3 is housed and mounted in the cavity 10 for the first time in the step of FIG.

Therefore, at least when the IC chip 3 is mounted, the heat application process necessary for stabilizing the characteristics of the oscillation frequency of the crystal unit 2 has been completed, and the number of heat histories applied to the IC chip 3 is reduced. Can be reduced. This improves the operational reliability of the IC chip 3.

In addition, according to the mounting order described above, the IC chip 3
It is possible to suppress the occurrence of the Cargendhal void phenomenon that occurs at the joint between the aluminum electrode and the Au bump of the IC.
Stable operation of the chip 3 and strong bonding can be achieved.

In addition, the monitor electrode pads 34 and 35 formed on the bottom surface of the cavity 10 show the oscillation characteristics of the crystal resonator 2 mounted on the container body 1 before the IC chip 10 is mounted and after each step. Can also be measured at. Depending on the result of the oscillation characteristics after each process, the container body 1 can be discarded with only the crystal resonator 2 mounted, so that the IC chip 3 is not wasted and the manufacturing process is not wasted. As a whole, it is a very inexpensive manufacturing method.

When writing the data necessary for temperature compensation, before the IC chip 3 is mounted and before the container body 1 is mounted.
The pure oscillation characteristic (frequency characteristic) of the crystal resonator 2 mounted on the substrate can be measured by using the monitor electrode pads 34 and 35 formed on the bottom surface of the cavity portion 10. Therefore, the data required for temperature compensation can be recognized in advance, and the data writing process required for temperature compensation written in the IC chip 3 after the IC chip 3 is mounted can be performed very efficiently. Become.

In the above embodiment, the method of connecting the IC chip 3 to the IC electrode pads 32 ... Of the container body 1 is ultrasonic welding using bumps.
Alternatively, a conductive adhesive may be interposed for connection. Alternatively, the input / output portion of the IC chip 3 may be formed on the upper surface side and connected by using a bonding wire.

In this case, a resin having a large shrinkage ratio should be avoided as the filling resin 7. This is to prevent the wire from falling over due to contraction stress. That is,
Even in the present embodiment, the I
As long as the C-chip 3 can be bonded with sufficient strength, the filling resin 7 may be formed of one type of resin material mainly having an emphasis on moisture resistance, without forming the filling resin 7 in a multilayer structure.

Although the partition 8 of the container body 1 has a multi-layered structure, the storage area for the crystal unit 2 and the IC chip 3 are used.
The partition portion 8 may be formed of a single-plate upper substrate as long as it is possible to completely prevent a leak from the storage area (cavity portion) of the above. In this case, the IC control terminal electrode 15
Since it is important that ~ 18 are not adjacent to the surface and bottom of the container body 1, the frame-shaped leg portion 9 has a multi-layer structure.

[0124]

According to the present invention, since the crystal resonator is mounted on the surface of the container body and the IC chip is mounted on the bottom surface side, a small temperature-compensated crystal oscillator having a small surface area is obtained.

Since the crystal unit and the IC chip can be housed in completely different regions, the oscillation operation of the crystal unit can be stabilized for a long period of time.

Further, the monitor electrode pad for measuring the oscillation characteristic of the crystal unit is formed on the bottom surface of the cavity portion and is not exposed on the outer surface of the container body. Therefore, even if the crystal unit is cut off from the outside, malfunction due to an external factor does not occur.

Further, by using the monitor electrode pad, the oscillation characteristic of the crystal unit alone can be measured before mounting the IC chip. Frequency adjustment of the crystal unit and selection of temperature compensation data become very easy.

Since the defect of the oscillation characteristic of the crystal resonator can be easily detected during the manufacturing process, wasteful consumption of the IC chip and unnecessary execution of the manufacturing process result in an inexpensive temperature-compensated crystal oscillator.

Further, after mounting the crystal unit on the surface of the container body, the IC chip is mounted. Therefore, the heat treatment necessary for mounting the crystal unit is not applied to the IC chip,
The operation reliability and mounting reliability of the IC chip can be improved. This also enables stable operation of the IC chip.

Thus, the manufacturing method of the small-sized, temperature-compensated crystal oscillator in which the oscillation operation and the temperature compensation operation by the IC chip are stabilized, stable predetermined oscillation is possible, and which is inexpensive.

[Brief description of drawings]

FIG. 1 is a sectional view of a temperature-compensated crystal oscillator according to the present invention.

FIG. 2 is a side view of a temperature-compensated crystal oscillator according to the present invention.

FIG. 3 is a top view of the temperature-compensated crystal oscillator according to the present invention with the lid omitted.

FIG. 4 is a bottom view of the temperature-compensated crystal oscillator according to the present invention with the filling resin omitted.

FIG. 5 is a schematic plan view showing an internal wiring pattern.

FIG. 6 is a process flow chart showing a manufacturing process.

FIG. 7 is a sectional view of a conventional temperature-compensated crystal oscillator.

FIG. 8 is a top view of a conventional temperature-compensated crystal oscillator omitted.

FIG. 9 is a bottom view of a conventional temperature-compensated crystal oscillator.

[Explanation of symbols]

1..Container body 2 ... Crystal oscillator 3 ... IC chip 4, 5, ... Electronic component elements 6 ... Metal lid 7 ... Filling resin 10 ... Cavity part 11-14 ... External terminal electrodes 15-18 ... IC control terminal electrode

Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H03B 5/32 H03H 3/02 H03H 9/02

Claims (2)

(57) [Claims] 1. A step of preparing a container body having a cavity portion on a lower surface thereof, an electrode pad on which a crystal resonator is mounted on an upper surface thereof, and a monitor electrode pad provided on an inner surface of the cavity portion, with implementing a quartz oscillator on the upper surface of the container body, and as engineering to connect the crystal resonator to said monitor electrode pad, while measuring the oscillation characteristic of the crystal oscillator with the monitor electrode pads, required A step of adjusting oscillation characteristics according to the above, a step of thermally aging the crystal unit, a step of covering a lid body that hermetically seals the crystal unit with a lid body, and an IC chip in the cavity section. And a step of writing temperature compensation data for temperature compensating the crystal oscillator in the IC chip. 2. A temperature-compensated crystal oscillator according to claim 1, wherein an IC control terminal electrode for connecting to an IC chip and writing temperature compensation data is formed on a side surface of the container body. Manufacturing method.