JPH11251839A - Piezoelectric device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the dislocation of an AT cut quartz oscillator, to prevent the deterioration of an oscillation characteristic and the occurrence of oscillation failure and the like and to prevent the deterioration of yield by forming the positioning pattern of a semiconductor integrated circuit or a piezoelectric oscillator on a base formed of ceramic. SOLUTION: At the positioning of an IC chip 2 on the electrode pattern 3 of a base 1 for chip-mounting, the center of the mounting area of the base 1 is detected based on positioning patterns 14a, 14b and 15 installed for the base 1 with picture recognition. Then, the rotary angle of the base 1 is detected. As a result, the IC chip 2 can precisely be chip-mounted on the base 1. At the time of mounting an AT cut quartz oscillator 6 on the base 1, the positions of a mounting electrode and the positioning pattern 15 are detected through image recognition, and the mounting position for the AT cut oscillator 6 is determined. Thus, the AT cut quarts oscillator 6 can be mounted precisely on the base 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a piezoelectric device having a semiconductor integrated circuit and a piezoelectric vibrator built in a package.

[0002]

2. Description of the Related Art In recent years, devices such as HDDs (hard disk drives), mobile computers, and small information devices such as IC cards, and mobile communication devices such as mobile phones and car phones have been remarkably reduced in size and thickness. Piezoelectric devices such as a piezoelectric oscillator and a real-time clock module are also required to be small and thin. At the same time, there is a need for a surface mount type piezoelectric device that can be mounted on both sides of a circuit board of an apparatus.

Therefore, an example of a conventional piezoelectric device is shown in FIGS. 1A and 1B using a one-chip semiconductor integrated circuit having an oscillation circuit and an AT-cut quartz oscillator as a piezoelectric oscillator.
Description will be made using the crystal oscillator shown in the structural diagram of FIG.

In the configuration of the conventional crystal oscillator shown in FIGS. 6A and 6B, an IC chip 101 having an oscillation circuit is provided.
Is bonded and fixed to the bottom surface of the base 102 formed of a ceramic insulating substrate with a conductive adhesive or the like, and a metal such as W (tungsten) or Mo (molybdenum) is formed on the outer periphery of the bottom surface of the base 102 by an Au wire bonding wire 103. , And are electrically connected to the Ni + Au-plated input / output electrode 104 and the like.

[0005] A rectangular type AT-cut quartz resonator 1
Reference numeral 05 is electrically connected to and fixed to the mount portion 106 of the base 102 with a conductive adhesive or the like. And N ₂
(Nitrogen) atmosphere or vacuum atmosphere is maintained, and the uppermost plating layer of the base 102 and the metal lid 107 are kept.
And a metal clad material such as solder formed on the lid 107 is melted at a high temperature and joined to hermetically seal.

[0006]

The conventional crystal oscillator described above has a configuration in which the gaps a and b between the AT-cut crystal resonator 105 and the base 102 are made as small as possible to make the package small and thin. ing. And base 1
In order to position and mount the AT-cut quartz crystal unit 105 in the space 02, an image recognition method using a part of the shape of the base 102 (for example, the shape of the uppermost plating layer) is adopted. However, in this method, the base 10
Since the positional accuracy of the uppermost plating layer is not obtained due to the misalignment between the ceramic sheets when laminating and sintering 2 and the misalignment in printing at the time of metallization, the misalignment of the AT-cut crystal pendulum 105 occurs. There is a problem that deterioration of vibration characteristics, oscillation failure, and the like occur, and the yield of the crystal oscillator is reduced.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art. It is an object of the present invention to provide a small and thin piezoelectric device such as a crystal oscillator having a thickness of 1 mm or less at a low cost. It is to be.

[0008]

According to the first aspect of the present invention,
In a piezoelectric device having a semiconductor integrated circuit and a piezoelectric vibrator incorporated in a package, a pattern for positioning the semiconductor integrated circuit or the piezoelectric vibrator is formed on a base made of ceramic.

A second aspect of the present invention is characterized in that, in the first aspect, the positioning pattern is metallized with a metal layer.

According to a third aspect of the present invention, in the second aspect, the positioning pattern is connected to a power supply line of an electrode pattern formed on the base.

According to a fourth aspect of the present invention, in the first aspect, at least one positioning pattern has a shape capable of specifying the center thereof.

According to a fifth aspect of the present invention, in the first aspect, the base is formed of a plurality of ceramic layers, and the positioning pattern crosses the inner wall surface of the base.

According to a sixth aspect of the present invention, in the first aspect, the semiconductor integrated circuit is mounted on the base by flip chip bonding.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the piezoelectric device of the present invention will be described with reference to a one-chip semiconductor integrated circuit having an oscillation circuit and a crystal oscillator using an AT-cut crystal resonator as a piezoelectric resonator. This will be described with reference to the drawings.

(Embodiment 1) FIG.
FIG. 9 is a structural view of a surface-mounted type crystal oscillator according to the inventions described in 4, 5, and 6.

As shown in the plan view of FIG. 1 (a) and the front view of FIG. 1 (b), a ceramic insulating substrate composed of three layers,
Seal ring 1 cut into a frame shape using an Fe-Ni alloy or the like
An electrode pattern 3 for connecting to a semiconductor integrated circuit (IC chip: hereinafter referred to as an IC chip) 2 is formed on the first layer of the base 1 formed of W (tungsten) or M
Metallized by printing or the like with a metal wiring material such as o (molybdenum). And Ni plating and Au on it
Plating is applied.

A bump 4 made of a metal such as Au is formed on an electrode pad of the IC chip 2 and is connected to the electrode pattern 3 formed on the base 1 by a flip chip bonding method. There are various processing methods for the flip chip bonding method, and the method used in this embodiment is a processing method using the conductive adhesive 5. Further, the reliability of the connection is increased by using an underfill material.

The AT-cut crystal unit 6 has a support 7 connected and fixed to a mount 8 provided on the second layer of the base 1 with a conductive adhesive 9.

Further, a metal lid (lid) 11 is positioned and fixed to the seal ring 12 of the base 1 and hermetically sealed by seam welding.

As described above, the crystal oscillator 13 of a small and thin surface mount package is completed.

Next, a flip chip bonding process for connecting the IC chip 2 to the electrode pattern 3 formed on the base 1 will be described in detail.

When the IC chip 2 is positioned on each electrode pattern 3 of the base 1 and mounted on the chip, the positioning patterns 14a provided on the base 1 by image recognition.
The center of the mount area of the base 1 is determined by using 14b and 15, and the rotation angle of the base 1 in the θ direction is detected.

An example of the above specific example will be described. The center line in the Y direction of the base 1 is detected by the positioning patterns 14a and 14b by a system such as an image recognition provided in the flip chip bonding apparatus. Positioning the center line in the X direction with the positioning patterns 14a, 15
And the center of the mount area of the base 1 is detected as the intersection. Also, positioning pattern 1
5, the rotation angle of the base 1 in the θ direction is detected.

With respect to the image recognition data, the IC chip 2 is aligned, mounted on the mount area of the base 1 with high precision, and further subjected to flip chip bonding.

The positioning patterns 14a, 14b and 15 are connected to the power supply line electrode patterns 16 and 17 formed on the base 1 at the shortest distance.
By connecting to the power supply line in this way, metallization can be performed simultaneously with the electrode patterns 16 and 17, and Ni plating and Au plating can be performed simultaneously.
In addition, a stable oscillation output can be obtained without the influence of unnecessary noise or the like.

Next, as shown in FIG. 2, the shape of the positioning pattern 15 is such that the center 21 thereof can be specified. With such a shape, the rotation angle of the base 1 in the θ direction can be accurately detected.

This shape is merely an example, and may be a circular shape as shown in FIG. 3, that is, any shape capable of specifying the center thereof.

Further, in this embodiment, the positioning pattern having a shape capable of specifying the center thereof is formed at one location, but a plurality or all of the positioning patterns may have this shape.

Next, the process of mounting the AT-cut crystal unit 6 on the base 1 will be described in detail.

As shown in FIG. 4, the AT-cut crystal unit 6 is connected and fixed to the mounting electrodes 22 and 23 of the mount unit 8 provided on the second layer of the base 1 by the conductive adhesive 9.

Here, since the gap between the AT-cut crystal unit 6 and the inner wall surface 24 of the second layer of the base 1 is very small,
The AT-cut quartz oscillator 6 must be built in this gap with high accuracy.

The positions of the mounting electrodes 22 and 23 and the positioning pattern 15 are detected by an image recognition system provided in the crystal oscillator mounting device in the same manner as the alignment of the IC chip 2 described above. Then, the mounting position of the AT-cut crystal unit 6 on the inner wall surface 24 is determined, and the AT-cut crystal unit 6 is mounted with high accuracy.

As shown in FIG. 4, a part or the end of the mounting electrodes 22 and 23 and the positioning pattern 15 intersects with the inner wall surface 24. By intersecting with the inner wall surface 24 in this manner, the edge of the inner wall surface 24 is detected by image recognition, and the mounting position of the AT-cut crystal resonator 6 is determined with high accuracy.

Embodiment 2 FIG. 5 is a perspective view showing a structure of a crystal oscillator according to another embodiment of the present invention. This is a structure in which a seal ring is removed from the configuration of FIG. It is composed of a ceramic base 31 composed of three layers, an IC chip 2, an AT-cut crystal unit 6, and a metal lid 32. A metal brazing material such as silver brazing, high melting point Pb-Sn based solder, or Au-Sn solder is clad on the Fe-Ni alloy-based lid 32. The lid 32 is positioned and fixed to the base 31, and the sealing portion is heated to the melting point of each brazing material to hermetically seal. This base 31
1, a positioning pattern is formed similarly to FIG.

As described above, by using highly reliable and inexpensive components such as ceramics and metals, the horizontal
~ 3.2mm, width 2 ~ 2.5mm, thickness 0.7 ~ 1.0
mm and a small and thin piezoelectric oscillator can be provided at low cost.

[0036]

According to the first, fourth, fifth and sixth aspects of the present invention, since the pattern for positioning the IC chip or the piezoelectric vibrator is formed on the base made of ceramic, the IC chip and the piezoelectric vibrator are formed. Image recognition for embedding a piezoelectric vibrator in a small-sized base can be performed with very high precision, eliminating poor conduction of IC chips and insufficient bonding strength, etc. In addition, misalignment of the piezoelectric vibrator and conductive adhesive This has the effect that a short-circuit failure or the like can be eliminated, and a piezoelectric oscillator having a good yield can be manufactured.

According to the second and third aspects of the present invention, the positioning pattern is metallized by the metal layer and can be metallized simultaneously with the electrode pattern by being connected to the power supply line. Plating and the like can be performed simultaneously. Further, there is an effect that a stable oscillation output can be obtained without the influence of unnecessary noise or the like.

[Brief description of the drawings]

FIG. 1 is a structural view of a piezoelectric device of the present invention. (A) is a top view. (B) is a front view.

FIG. 2 is an enlarged view of a positioning pattern of the piezoelectric device of the present invention.

FIG. 3 is an enlarged view of another positioning pattern of the piezoelectric device of the present invention.

FIG. 4 is a layout view of a mount portion of a quartz oscillator of the piezoelectric device according to the present invention.

FIG. 5 is a structural view of another embodiment of the present invention.

FIG. 6 is a structural view of a conventional piezoelectric device. (A) is a top view. (B) is a front view.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 base 2 IC chip 3 electrode pattern 4 bump 5 conductive adhesive 6 AT-cut crystal vibrator 7 support 8 mount 9 conductive adhesive 11 lid 12 seal ring 13 crystal oscillator 14a, 14b positioning pattern 15 positioning pattern 16, 17 Electrode pattern 21 Center 22, 23 Mounting electrode 24 Inner wall surface 31 Base 32 Lid 101 IC chip 102 Base 103 Au wire bonding wire 104 I / O electrode 105 AT-cut crystal oscillator 106 Mounting part 107 Lid

Claims (6)

[Claims] 1. A piezoelectric device in which a semiconductor integrated circuit and a piezoelectric vibrator are incorporated in a package, wherein a pattern for positioning the semiconductor integrated circuit or the piezoelectric vibrator is formed on a base made of ceramic. Characteristic piezoelectric device. 2. The piezoelectric device according to claim 1, wherein said positioning pattern is metallized with a metal layer in a piezoelectric device having a semiconductor integrated circuit and a piezoelectric vibrator built in a package. 3. A piezoelectric device in which a semiconductor integrated circuit and a piezoelectric vibrator are built in a package, wherein the positioning pattern is connected to a power line of an electrode pattern formed on the base. Item 3. The piezoelectric device according to Item 2. 4. A piezoelectric device having a semiconductor integrated circuit and a piezoelectric vibrator built in a package, wherein at least one of the positioning patterns has a shape capable of specifying the center thereof. 2. The piezoelectric device according to 1. 5. A piezoelectric device having a semiconductor integrated circuit and a piezoelectric vibrator incorporated in a package, wherein the base is formed of a plurality of ceramic layers, and the positioning pattern intersects an inner wall surface of the base. The piezoelectric device according to claim 1, wherein: 6. A piezoelectric device according to claim 1, wherein said semiconductor integrated circuit is mounted on said base by flip-chip bonding in a piezoelectric device having a semiconductor integrated circuit and a piezoelectric vibrator incorporated in a package. .