JP2001274653A - Piezo device - Google Patents

Abstract

(57) Abstract: Provided is a highly reliable, inexpensive, small and thin piezoelectric device which is excellent in holding structure of a piezoelectric vibrator and is provided in a piezoelectric device having a semiconductor integrated circuit and a piezoelectric vibrator built in a package. In a piezoelectric device in which a semiconductor integrated circuit and a piezoelectric vibrator are incorporated in a package, means for holding the piezoelectric vibrator in parallel uses an insulating sphere or an insulating sphere coated with a metal. Surface mount type piezoelectric device characterized by its structure.

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 oscillators and voltage-controlled oscillators (VCX
O), a temperature-compensated oscillator (TCXO), a SAW oscillator, and a piezoelectric device such as a real-time clock module are also required to be small and thin. In addition,
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.

[0005] In view of this, an example of a conventional piezoelectric device is shown in FIGS. 5A and 5A in which a one-chip semiconductor integrated circuit having an oscillation circuit and an AT-cut quartz oscillator are used as the piezoelectric oscillator.
Description will be made using the crystal oscillator shown in the structural diagram of FIG.

[0005] In the configuration of the conventional crystal oscillator shown in FIGS. 5A and 5B, 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 by a conductive adhesive or the like, and a metal such as W (tungsten) or Mo (molybdenum) is formed on an outer peripheral portion 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
While maintaining the inside in a (nitrogen) atmosphere or a vacuum atmosphere, the seal ring 107 at the top of the base 102 and the metal lid 108 are joined by seam welding to hermetically seal them.

[0006]

The above-described conventional crystal oscillator requires an area around the IC chip 101 for wiring the Au wire bonding wire 103.
In addition, in the thickness direction of the package, the crystal oscillator is required to secure the loop height of the Au wire bonding wire 103 and to secure a gap between the Au wire bonding wire 103 and the AT-cut crystal oscillator 105. Are small and thin.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in the prior art, and it is an object of the present invention to secure a loop height of an Au wire bonding wire, and particularly to secure an Au wire bonding wire. It is an object to provide a piezoelectric device such as a crystal oscillator such as a crystal oscillator having a small size, a small size, and a thickness of 1 mm or less using a structure for accurately and stably realizing a gap between the crystal oscillator and an AT-cut crystal resonator.

[0008]

According to the first aspect of the present invention,
In a piezoelectric device in which a semiconductor integrated circuit and a piezoelectric vibrator are built in a package formed of a wiring substrate, the piezoelectric vibrator is mounted with a resin adhesive and held at at least three points including the electrode portion of the piezoelectric vibrator. It is characterized by having.

According to a second aspect of the present invention, in a piezoelectric device in which a semiconductor integrated circuit and a piezoelectric vibrator are incorporated in a package formed of a wiring board, the piezoelectric vibrator has an electrode portion mounted with a conductive adhesive. And means for holding the piezoelectric vibrator parallel to the mount portion.

The invention according to claim 3 is characterized in that the means for holding the piezoelectric vibrator in parallel uses an insulating sphere or an insulating sphere coated with a metal.

According to a fourth aspect of the present invention, in the third aspect, the insulating sphere is a spherical filler of an organic glass type or an organic resin type.

According to a fifth aspect of the present invention, in the fourth aspect, the insulating sphere is contained in a conductive adhesive.

According to a sixth aspect of the present invention, in the second aspect, the means for holding the piezoelectric vibrator in parallel is a plurality of bumps made of metal.

According to a seventh aspect of the present invention, the means for holding the piezoelectric vibrator in parallel is a plurality of bumps formed by metal bonding wires.

According to an eighth aspect of the present invention, in the first aspect, the piezoelectric vibrator is mounted with a resin adhesive and is held at three points including at least the electrode portion of the piezoelectric vibrator. Characterized in that the sphere is contained.

According to a ninth aspect of the present invention, in the first aspect, the piezoelectric vibrator is mounted with a resin adhesive and held at at least three points including the electrode portion of the piezoelectric vibrator. A plurality of bumps are formed.

According to a tenth aspect of the present invention, in a piezoelectric device in which a semiconductor integrated circuit and a piezoelectric vibrator are built in a package formed of a wiring board, the piezoelectric vibrator is mounted with a resin adhesive, and a groove is formed in the mounting portion. It is characterized in that a plurality of resin adhesives are applied along the grooves.

[0018]

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.
It is a structural diagram of the crystal oscillator of the surface mounting type concerning the invention of 4, 5, 8, 10.

As shown in the plan view of FIG. 1 (a) and the front view of FIG. 1 (b), a ceramic insulating substrate having at least three layers, and a seal ring cut into a frame shape with 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 and second layers of the base 1 formed of W (tungsten) or Mo (molybdenum). And metallized by printing or the like. Then, Ni plating, Au plating or the like is applied thereon.

An appropriate amount of a conductive adhesive 4 such as Ag paste is applied to the first layer of the base 1 and an IC chip 2 is mounted thereon. Then, the conductive adhesive 4 is cured at a high temperature of about 200 ° C., and the IC chip 2 is fixed.

Further, an Au wire bonding line 5 is wired from the electrode pad of the IC chip 2 to the electrode pattern 3 by a wire bonding apparatus. The Au wire bonding line 5 has a low loop and a very short wiring length.

The AT-cut crystal unit 6 has its support 7 connected and fixed to a mount 8 provided on the third layer of the base 1 with a conductive adhesive 9. The tip portion 10 of the AT-cut crystal resonator 6 is also held and fixed to the mount portion 11 provided on the third layer of the base 1 on the side opposite to the mount portion 8 with an insulating adhesive 12.

Further, a metal lid (lid) 14 is positioned and fixed to a seal ring 13 cut out in a frame shape from an Fe--Ni alloy or the like of the base 1, and hermetically sealed by seam welding. ing.

As described above, the crystal oscillator 15 of the small and thin surface mount package is completed.

Here, the structure of the mount section 8 for mounting the AT-cut crystal unit 6 and the mounting method will be described in detail.

FIG. 2 is an enlarged view of the mount section 8. FIG.
As shown in the plan view of (a) and the front view of FIG.
The mount electrode portion 21 formed in at least two layers includes
A groove 22 is formed substantially at the center of the mount electrode portion 21. Then, a silicon-based conductive adhesive 9 having excellent heat resistance, for example, is applied to the mount electrode portion 21 with a syringe or the like. In this embodiment, the mount electrode unit 2
1 along the groove 22 with a diameter of 0.3 to 0.1 mm.
Coating is performed at two locations with a coating diameter of about 4 mm. As described above, by applying the coating at two locations to the mount portion 8 of the AT-cut crystal resonator 6, a sufficient bonding area can be secured in the short-side direction of the AT-cut crystal resonator 6, and The vibrator 6 is securely held and fixed. Also, by providing the groove 22, the conductive adhesive 9 is applied to the mount electrode portion 21 by the AT-cut quartz oscillator 6.
This spreads in the lateral direction that has little effect on the vibration mode of the first embodiment, and secures an adhesion area with the AT-cut crystal resonator 6.

Further, the conductive adhesive 9 contains an appropriate amount of a spherical filler 23 such as an epoxy resin. In the case of this embodiment, the diameter of the spherical filler 23 is φ30 to 40 μm.
m is used. Similarly, the insulating adhesive 12 used for the mounting portion 11 has a diameter of 30 to 40 μm.
A degree of spherical filler 23 is contained.

As described above, by containing the spherical filler 23 in the conductive adhesive 9 and the insulating adhesive 12,
The distance between the AT-cut crystal unit 6 and the mount unit 8 becomes constant, and the AT-cut crystal unit 6 can be held in parallel. By holding the AT-cut crystal resonator 6 in parallel in this manner, the space between the AT-cut crystal resonator 6 and the Au wire bonding wire 5 can be reliably ensured, and this has the effect of solving problems such as short-circuit failure.

Further, a metal material coated on the spherical filler 23 may be used, and the material and surface treatment of the spherical filler 23 are not particularly limited.

Thus, the AT-cut quartz oscillator 6
However, the base 1 mounted on the mounting portion 8 is annealed at a high temperature, and the conductive adhesive 9 and the insulating adhesive 12
By hardening, the AT-cut crystal resonator 6 is securely connected and fixed to the mount electrode 21 with high accuracy.

(Embodiment 2) FIG. 3 is a structural view of a surface mount type crystal oscillator according to the sixth, seventh and ninth aspects of the present invention.

As shown in the plan view of FIG. 3A and the front view of FIG. 3B, a ceramic insulating substrate composed of at least three layers, and a seal ring cut into a frame shape with an Fe—Ni alloy or the like. An electrode pattern 33 for connecting to a semiconductor integrated circuit (IC chip: hereinafter referred to as an IC chip) 32 is formed on a first layer of a base 31 formed of a metal wiring such as W (tungsten) or Mo (molybdenum). Metallized by printing or the like with the material. And Ni on top
Plating and Au plating are performed.

The electrode pads of the IC chip 32 have Au
And the like, and are bonded to the electrode pattern 33 formed on the base 1 using a conductive adhesive 35 by a flip chip bonding method. There are various processing methods for this flip chip bonding method, and the method used in the present invention is a processing method in which a conductive adhesive is used for a joint portion and bonding is performed by applying appropriate pressure and temperature. is there.

The AT-cut crystal unit 36 has a support 37 connected and fixed to a mount 38 provided on the third layer of the base 31 with a conductive adhesive 39.

Further, a metal lid (lid) 42 is positioned and fixed to a seal ring 41 cut out in a frame shape with an Fe—Ni alloy or the like of the base 1 and is hermetically sealed by seam welding. I have.

As described above, the crystal oscillator 43 of a small and thin surface mount package is completed.

Here, the structure of the mount section 38 for mounting the AT-cut crystal unit 36 and the mounting method will be described in detail.

FIG. 4 is an enlarged view of the mount 38. As shown in the plan view of FIG. 4A and the front view of FIG. 4B, the mount electrode portion 51 formed in at least two layers has substantially the center of the mount electrode portion 51 as in the first embodiment. Is formed with a groove 52. Then, a plurality of Au bumps 53 formed by Au wire bonding lines are bump-bonded to the mount electrode portion 51.

Here, the diameter of the Au bump 53 is about φ80.
μm and a height of about 30 to 40 μm.

Then, for example, a silicon-based conductive adhesive 39 having excellent heat resistance is applied drop-wise around the Au bump 53 with a syringe or the like.

As in the case of the first embodiment, the diameter of the mount section opposite to the mount section 38 is about φ80 μm.
An Au bump 53 having a height of about 30 to 40 μm is bump-bonded.

As described above, the Au is applied to the mount electrode 51 and the like.
By providing the bumps 53, the distance between the AT-cut crystal unit 36 and the mount unit 38 becomes constant, and the AT-cut crystal unit 36 can be held in parallel. By holding the AT-cut quartz oscillator 36 in parallel in this way, Au
The distance from the wire bonding wire 35 can be reliably ensured, which has the effect of solving problems such as short-circuit failure.

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 highly reliable piezoelectric oscillator having a small thickness and a small thickness can be provided at low cost.

As described above, the crystal oscillator using the one-chip semiconductor integrated circuit having the oscillation circuit and the AT-cut crystal resonator as the piezoelectric vibrator has been described as an example, but the present invention is not limited thereto. For example, a voltage-controlled crystal oscillator (V
The present invention can be applied to all piezoelectric devices including a semiconductor integrated circuit such as a CXO), a temperature compensated crystal oscillator (TCXO), a SAW oscillator, and a real-time clock module.

[0046]

According to the first, second, third, fourth, fifth and eighth aspects of the present invention, the conductive adhesive and the insulating adhesive contain a spherical filler so that the AT-cut quartz resonator can be used. The distance between the mount portions becomes constant, and the AT-cut quartz crystal unit can be held in parallel. By holding the AT-cut crystal unit in parallel in this manner, the space between the AT-cut crystal unit and the Au wire bonding line can be reliably ensured, and a small and thin structurally superior piezoelectric oscillator free from short-circuit failure can be provided. Have.

Further, by containing a spherical filler,
When mounting an AT-cut quartz crystal unit, it can be stably pressurized with a constant load, so the adhesion strength between the AT-cut quartz crystal unit and the conductive or insulating adhesive is improved, and a piezoelectric device with excellent drop impact, etc. This has the effect of providing an oscillator.

According to the sixth, seventh, and ninth aspects of the present invention, by providing Au bumps on the mount electrode portion, the distance between the AT-cut quartz crystal unit and the mount portion becomes constant,
The cut crystal unit can be held in parallel. A
By holding the T-cut quartz resonator in parallel, Au
This has the effect that the interval between the wire bonding wire and the wire bonding wire can be reliably ensured, and a structurally excellent piezoelectric oscillator free from short-circuit failure or the like can be provided.

Also, by providing Au bumps under the AT-cut quartz resonator, it is possible to stably apply a constant load when mounting the AT-cut quartz resonator. In addition, the adhesive strength with the insulating adhesive is improved, and the piezoelectric oscillator excellent in drop impact and the like can be provided.

According to the tenth aspect of the present invention, the AT-cut quartz resonator is mounted with a conductive adhesive, a groove is formed in the mount portion, and a plurality of conductive adhesives are applied along the groove. I have. By applying at least two portions to the mount portion of the AT-cut quartz resonator as described above, it is possible to secure a sufficient bonding area in the lateral direction of the AT-cut quartz resonator, This has the effect of securely holding and fixing the child. Thereby, there is an effect that a small and thin piezoelectric oscillator having excellent characteristics such as a drop impact can be provided.

By providing the groove, the conductive adhesive spreads in the lateral direction with respect to the mount electrode portion, and has an effect that a sufficient adhesive area with the AT-cut quartz crystal resonator can be secured. Further, a highly accurate and highly reliable bonding structure of the crystal unit which does not affect the vibration mode of the AT-cut crystal unit can be realized, and a high quality piezoelectric oscillator can be provided.

[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 mount portion of the piezoelectric device of the present invention.
(A) is a top view. (B) is a front view.

FIG. 3 is another structural view of the piezoelectric device of the present invention. (A)
Is a plan view. (B) is a front view.

FIG. 4 is an enlarged view of another mounting portion of the piezoelectric device of the present invention. (A) is a top view. (B) is a front view.

FIG. 5 is a structural view of a conventional piezoelectric device. (A) is a top view. (B) is a front view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base 2 IC chip 3 Electrode pattern 4 Conductive adhesive 5 Au wire bonding wire 6 AT cut crystal oscillator 7 Support part 8 Mount part 9 Conductive adhesive 10 Tip part 11 Mount part 12 Insulating adhesive 13 Seal ring 14 Lid 15 Crystal oscillator 21 Mount electrode part 22 Groove 23 Spherical filler 31 Base 32 IC chip 33 Electrode pattern 34 Bump 35 Conductive adhesive 36 AT-cut quartz oscillator 37 Support part 38 Mount part 39 Conductive adhesive 41 Seal ring 42 Lid 43 Crystal Oscillator 51 Mount Electrode 52 Groove 53 Au Bump 101 IC Chip 102 Base 103 Au Wire Bonding Wire 104 Input / Output Electrode 105 AT Cut Quartz Crystal Resonator 106 Mounting Part 107 Seal Ring 108 Lid

Claims (10)

[Claims] 1. A piezoelectric device in which a semiconductor integrated circuit and a piezoelectric vibrator are incorporated in a package formed of a wiring board, wherein the piezoelectric vibrator is mounted with a resin adhesive, and at least an electrode portion of the piezoelectric vibrator is provided. A piezoelectric device characterized by being held at three points including: 2. A piezoelectric device in which a semiconductor integrated circuit and a piezoelectric vibrator are incorporated in a package formed of a wiring substrate, wherein the piezoelectric vibrator has an electrode portion mounted with a conductive adhesive, and the mount portion has A piezoelectric device using means for holding a piezoelectric vibrator in parallel. 3. The means for holding the piezoelectric vibrator in parallel,
3. The piezoelectric device according to claim 2, wherein an insulating sphere or an insulating sphere coated with a metal is used. 4. The piezoelectric device according to claim 3, wherein the insulating sphere is an organic glass-based or organic resin-based spherical filler. 5. The piezoelectric device according to claim 4, wherein the insulating sphere is contained in the conductive adhesive. 6. A means for holding said piezoelectric vibrator in parallel,
3. The piezoelectric device according to claim 2, comprising a plurality of bumps formed of metal. 7. A means for holding said piezoelectric vibrator in parallel,
7. The piezoelectric device according to claim 6, comprising a plurality of bumps formed by metal bonding lines. 8. The method according to claim 1, wherein said piezoelectric vibrator is mounted with a resin adhesive and held at at least three points including an electrode portion of said piezoelectric vibrator, and said resin adhesive contains an insulating sphere. The piezoelectric device according to claim 1, wherein: 9. The piezoelectric vibrator is mounted with a resin adhesive, held at at least three points including an electrode portion of the piezoelectric vibrator, and a plurality of metal bumps are formed on the mount portion. The piezoelectric device according to claim 1, wherein 10. A piezoelectric device in which a semiconductor integrated circuit and a piezoelectric vibrator are built in a package formed of a wiring board, wherein the piezoelectric vibrator is mounted with a resin adhesive, a groove is formed in a mount portion, and the groove is formed. Characterized in that a resin adhesive is applied at a plurality of locations along the piezoelectric device.