JP3375445B2 - How to support the crystal resonator element - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric vibrator, and more particularly to a method of holding a crystal vibrating piece which is a constituent element of a crystal vibrator.

[0002]

2. Description of the Related Art Crystal oscillators provided with a flat crystal resonator element such as an AT crystal resonator element are classified into a lead type using airtight terminals and a surface mount type so-called SMD type.

Of these, the SMD crystal oscillator is suitable for mounting on a printed wiring board as a clock source for microcomputers, communication devices and the like, and has been widely used in recent years.

As a conventionally known method for supporting the crystal vibrating piece in the SMD crystal unit, as a first method, as shown in FIG. 7, a flat plate type crystal vibrating piece 6 is bonded to the substrate 1 by an adhesive 20. There is a method of cantilever support above.

As a second method, as shown in FIG. 8, there is a method of supporting the convex type quartz vibrating piece 6 on the substrate 1 in a cantilever manner with an adhesive 20.

As a third method, Japanese Patent Laid-Open No. 4-36711
As described in Japanese Patent Publication No. 1 and shown in FIG. 9, a dedicated buffer spring 22 in which a crystal vibrating piece 6 is attached to a metal wiring 7 on a substrate 1
There is a method of supporting both ends by an adhesive agent 20 on the top.

Further, as a fourth method, as shown in FIG. 10, there is a method of supporting both sides of a crystal vibrating piece with an adhesive 20 on a general supporting spring 15 attached to a metal wiring 7 on a substrate 1. .

Here, as shown in FIGS. 7, 8, 9, and 10, the substrate 1 is provided with the metal wiring 7, the crystal vibrating piece 6 is provided with the electrode 11, and is electrically conductively fixed by the conductive adhesive 20. There is. The cap 10 is bonded to the peripheral portion of the substrate 1 by means such as a sealant (not shown) and sealed to complete the crystal unit.

[0009]

In the above-mentioned first and second methods, the adhesive 20 is conventionally 150 to 30.
A thermosetting adhesive that solidifies at 0 ° C is used.
When the adhesive is heated and cured, the adhesive contracts and the contraction causes the crystal vibrating piece 6 to receive a moment to rotate counterclockwise in FIGS. 7 and 8, and the tip of the vibrating piece separates from the substrate 1. Lift up.

The amount of lifting is larger in the second method using the convex type crystal vibrating piece shown in FIG. 8 than in the first method using the flat plate type crystal vibrating piece shown in FIG. However, in both cases of the first and second methods, there is no change in lifting.

As a result, in any case, the space required for the clearance between the substrate 1 and the cap 10 increases, and the crystal resonator cannot be sufficiently thinned. On the lower side of the crystal vibrating piece 6, when the adhesive 20 is heated and cured, the solvent cannot be sufficiently degassed, and bubbles or voids are generated in the adhesive 20, so that the adhesive strength is not sufficiently exerted. The impact resistance is also reduced.

In the third method described above, since the dedicated buffer spring 22 is used as shown in FIG. 9, the buffer spring 2 is used.
Because of the space due to 2, the supporting position of the crystal vibrating piece 6 becomes high, which makes it difficult to thin the crystal resonator. The cost is increased by the amount of the member of the buffer spring 22.

In the fourth method, as shown in FIG. 10, the crystal vibrating piece 6 contracts when the adhesive 20 is hardened, and the falling corner portion 26 of the supporting spring 15 is used as a fulcrum to support the crystal vibrating piece. The left end portion of 6 receives a moment arrow 27 in the counterclockwise direction at the left end portion thereof and a clockwise moment at the right end portion thereof, and is deformed into a convex shape to generate strain stress as indicated by arrows 28 and 29. The generation of this strain stress deteriorates the characteristics of the crystal unit.

The present invention solves the above-mentioned problems of the conventional example with respect to the method of supporting the crystal resonator element in the SMD type crystal resonator, and enables the crystal resonator to be made thinner, the shock resistance to be improved, and the cost to be reduced. The purpose is to

[0015]

As a first means for solving the above problems, the present invention provides a method for supporting a crystal vibrating piece in which a holding portion holds the crystal vibrating piece in the holding portion. In the method for supporting a crystal vibrating piece that is supported by a method, a step of applying a first adhesive to the holding part, and a step of evaporating a solvent of the first adhesive applied to the holding part to perform the first adhesion. Temporary curing step of making the agent half-cured or more, and step of applying a second adhesive on the first adhesive
And an end portion of the crystal vibrating piece is the first adhesive and
Placing the crystal vibrating piece on the holding part so as to come into contact with a second adhesive, and adding an additional second adhesive to fix the end of the crystal vibrating piece. End of
The method includes a step of applying to the surface and a step of solidifying the first and second adhesives at a curing temperature .
When the adhesive cures and shrinks,
It is characterized by being blocked by the first adhesive . As a second means, the present invention provides a method of supporting a crystal vibrating piece in which a crystal vibrating piece is supported by a holding portion, a step of applying a first adhesive to the holding portion, and a step of applying the first adhesive to the holding portion. A temporary curing step of evaporating the solvent of the first adhesive to bring the first adhesive into a semi-hardened state or more; and a step of applying a second adhesive to an end portion of the crystal vibrating piece. Placing the crystal vibrating piece on the holding portion so that an end portion of the crystal vibrating piece contacts the first adhesive;
And a step of solidifying the second adhesive at a curing temperature, the quartz crystal when the first and second adhesives cure and shrink.
It is characterized in that the piece is prevented from standing up by the first adhesive .

As a third means for solving the above-mentioned problems, the present invention provides the temporary cure process according to the first means.
After that, the shape of the first adhesive is the end of the crystal vibrating piece.
It is characterized in that it has a shape substantially similar to the shape of the part.

As a fourth means for solving the above-mentioned problems, the present invention is the same as the first means, except that the first adhesive is used.
The second adhesive is an adhesive made of the same material . In addition, as a fifth means, the above first to fourth
A method for manufacturing a crystal unit using any one of the methods.
It

[0018]

According to the present invention, the first adhesive is temporarily cured by heating or the like to such an extent that at least the solvent is blown, that is, the solvent is evaporated, and then the second adhesive is applied onto the first adhesive . Contact
Apply the adhesive, and make sure that the end of the crystal vibrating piece is
Place the crystal vibrating piece on the holding part so that it will come into contact with the adhesive of 2.
Position, and add an additional piece to secure the end of the crystal vibrating piece.
The second adhesive is applied to the end surface of the crystal vibrating piece.
It The second adhesive may be applied to the end of the crystal vibrating piece in advance.

[0019] At this time, since the first adhesive is accurate positioning of the crystal resonator element and the role of the spacer by a substantially similar shape of the shape of the quartz crystal vibrating element, the second adhesive is cured Temperature Even if the crystal vibrating piece is solidified and contracted by heating at 1, the movement or deformation of the crystal vibrating piece due to this is effectively prevented.

Further, since the first adhesive located under the crystal vibrating piece can be sufficiently degassed by heating before mounting the crystal vibrating piece, generation of voids can be prevented. Further, if the first adhesive and the second adhesive are the same or of the same quality, they are easily compatible with each other. With these, the crystal vibrating piece can be firmly bonded to the holding portion.

For the above reason, in the case of cantilever support, rising of the free end of the crystal vibrating reed at the time of bonding is prevented, so that the crystal resonator can be sufficiently thinned.

The increase in the adhesive strength improves the impact resistance of the crystal unit.

Further, as the quartz crystal vibrating piece is held horizontally, as will be described later, since the frequency adjusting vapor deposition pattern can be accurately formed, the characteristics of the quartz oscillator are improved as compared with the conventional case.

In the case of both-sided support, deformation of the crystal vibrating piece during adhesion is prevented, so that the strain stress generated in the crystal vibrating piece due to the deformation is drastically reduced, and the crystal resonator is more than conventional. The characteristics of are improved.

Since it is possible to sufficiently secure the characteristics of the crystal unit by using an ordinary support spring without using a dedicated buffer spring for supporting the crystal vibrating piece,
The cost of the crystal unit can be reduced and the thickness can be reduced.

[0026]

【Example】

(Embodiment 1) As a first embodiment of the present invention, a method of supporting a crystal vibrating piece which is cantilever-supported by an adhesive on a substrate of an SMD crystal resonator will be described with reference to FIG. FIG. 1 is a process chart showing the method of this embodiment. In FIG. 1, the metal wiring provided on the substrate 1 and the electrodes on the surface of the crystal vibrating piece 6 are not shown.

In ST1, the substrate 1 having the relief portion 2 is prepared.

In ST2, the first adhesive 3 is applied to the holding portion 4 of the substrate 1 by means of screen printing, dispenser, stamping or the like.

As the first adhesive 3, a conductive polymer type thermoplastic adhesive is used when it is heated to a high temperature in a post process such as sealing.

When the latter is not heated to a high temperature, a conductive epoxy thermosetting adhesive generally used as the first adhesive 3 can be used.

In ST3, heating is carried out to perform temporary curing to remove the solvent of the first adhesive 3, that is, to evaporate the solvent.
Then, at least the semi-cured state is such that the adhesive does not stick to the adhesive surface when it is touched.

In ST4, the second adhesive is placed on the first adhesive 3.
Adhesive 25 is applied. Here, as the second adhesive 25, the same or similar adhesive as the first adhesive 3 may be used.

Although not shown in the drawing instead of the above in ST3, a supplementary first adhesive is further applied onto the first adhesive 3 and then temporary curing is performed, and then S is further applied.
The second adhesive 25 may be applied as in T4.

Convex crystal vibration in ST5
The end of the piece 6 is placed on the substrate 1. At this time, (a) first
While maintaining its shape, the adhesive 3 comes into contact with the end of the crystal vibrating piece 6 for positioning. (B) When the second adhesive 25 is applied in ST4, the second adhesive 25 flows and fills the space between the positioned crystal vibrating piece 6 and the holding portion 4 and the peripheral space.

In ST6, an additional second adhesive 5 is further added.
Is applied to the surface of the end portion of the crystal vibrating piece 6 and the surface of the second adhesive 25 or the first adhesive 3 applied in ST4 by a dispenser.

Instead of ST5 and ST6, the second adhesive 5 is applied to the end of the crystal vibrating piece 6 in advance so that the end comes into contact with the first adhesive 3 as will be described later. The crystal vibrating piece 6 may be mounted on the substrate 1.

In ST7, the first adhesive 3 and the second adhesive 3
A final cure is performed by including the adhesive 5 in the above to solidify the whole.

At this time, the portion of the second adhesive 5 contracts, but the portion of the first adhesive 3 positions the crystal vibrating piece 6 with almost no deformation, so that the free end 6b is lifted up by the substrate 1. And the crystal vibrating piece 6 is very small so that a gap is generated.

A crystal resonator manufactured by the method of this embodiment will be described with reference to the drawings. In the following description, the case where the adhesive 25 of ST4 is not applied will be described. FIG. 2 is a diagram showing an example of a completed SMD crystal resonator formed by supporting a crystal resonator element by the method of this embodiment. As shown in FIG. 2, the metal wiring 7 is routed around the substrate 1 made of an insulating material, and the first wiring 3 and the second wiring 5 are used on the metal wiring 7 as described above. The crystal vibrating piece 6 is adhered and held. At this time, since these adhesives are electrically conductive, they are also electrically connected.
The electrodes on the surface of the crystal vibrating piece 6 are not shown. Both the first adhesive 3 and the second adhesive 5 are conductive polymer thermoplastic adhesives.

In the peripheral portion of the substrate 1, an insulating protective film 8 is formed across the metal wiring 7, and a cap 10 is bonded onto the protective film 8 with a low melting point glass 9 to seal the quartz resonator. Complete. At this time, even if the low-melting glass 9 is heated to a melting temperature, the first adhesive 3 and the second adhesive 5 are both thermoplastic, so that they are thermally decomposed to generate gas and the substrate 1 Does not separate from the substrate 1 or the crystal vibrating piece 6 due to the stress due to the difference in linear expansion of the crystal vibrating piece 6.

FIG. 3 is a view showing another example of a completed SMD crystal resonator formed by supporting a crystal resonator element by the method of this embodiment. As shown in FIG. 3, the metal wiring 7 is routed around the substrate 1 made of an insulating material, and the first wiring is formed on the metal wiring 7.
The crystal vibrating piece 6 is bonded and held and electrically connected by the adhesive 3 and the second adhesive 5 as described above. The electrodes on the surface of the crystal vibrating piece 6 are not shown. Here, the first adhesive 3 and the second adhesive 5 are both commonly used conductive epoxy thermosetting adhesives.

Next, in the peripheral portion of the substrate 1, the cap 10 is joined and sealed by welding or the organic sealant 18 without heating the first adhesive 3 and the second adhesive 5 to a high temperature. Complete the oscillator.

The effects of this embodiment will be described. Figure 1,
As shown in FIGS. 2 and 3, the crystal vibrating piece 6 is horizontal or substantially horizontal to the substrate 1. Generally the first adhesive 3
And is placed at a slight angle, and becomes horizontal by the final curing of the first adhesive 3 and the second adhesive 5.

FIG. 4 is a view showing a method of forming the frequency adjusting vapor deposition pattern 13 on the surface of the quartz crystal vibrating piece 6 by using the mask 12. According to the supporting method of the present embodiment, the crystal vibrating piece 6 can be held horizontally as shown in FIG. 4, so that the positional relationship between the crystal vibrating piece 6 and the mask 12 is always constant, and the vapor deposition pattern 13 for frequency adjustment is used. Can be accurately formed at a predetermined position. As a result, the characteristics of the crystal unit can be improved as compared with the conventional one.

The above-mentioned effect on the horizontal holding and accurate formation of the vapor deposition pattern is particularly remarkable in the case of the convex type crystal vibrating piece, but a sufficient effect can be obtained also in the case of the flat plate type crystal vibrating piece.

The crystal resonator can be thinned for the same reason as described above.

The shock resistance of the crystal unit is improved for the same reason as described above.

(Embodiment 2) As a second embodiment of the present invention, referring to FIG. 5, a method for supporting both sides of a crystal vibrating piece with an adhesive on a pair of support springs provided on a substrate will be described. explain. FIG. 5 is a process drawing showing the supporting method of this embodiment. In FIG. 5, the electrodes on the surface of the crystal vibrating piece 6 are not shown.

In ST1, the substrate 1 provided with the pair of support springs 15 is prepared. The substrate 1 includes a metal wiring 7, and a pair of support springs 15 are joined to the metal wiring 7 by brazing or the like.

In ST2, the first adhesive 3 is applied to the corner portion of the upper surface of the support spring 15. The type of this adhesive is the same as in the case of the first embodiment.

In ST3, the first adhesive 3 is semi-cured. At this time, the first adhesive 3 wets the support spring 15 and contracts to reduce its volume, so that its surface shape becomes a slope adapted to the end of the convex type quartz vibrating piece.

In ST4, a second adhesive 5 of the same quality or the same quality as the first adhesive 3 is applied to both ends of the convex type quartz vibrating piece 6 independently of the steps of ST1 to ST3.

In ST5, the second adhesive 5 applied to both ends of the convex type quartz vibrating piece 6 in ST4 is overlaid on the first adhesive 3 applied to the support spring 15 in ST3. Place it like this.

In ST6, the first adhesive 3 and the second adhesive 3
The adhesive 5 is finally cured, and the step of supporting the crystal vibrating piece 6 is completed. As a result, the crystal vibrating piece 6 is bonded and held to the support spring 15 by these adhesives. At this time, since these adhesives are conductive, the crystal vibrating piece 6 and the support spring 1 are
5 electrical connections are also made.

[0055]

[0056]

[0057]

FIG. 6 is a view showing a completed crystal unit using the supporting method of this embodiment. After the end of the supporting process,
As shown in FIG. 6, the cap 10 is bonded to the peripheral portion of the substrate 1 with the encapsulant 18 to perform encapsulation to complete the crystal unit.

The effects of this embodiment will be described. According to the supporting method of this embodiment, the supporting spring 15 and the adhesive are well compatible with each other. The first adhesive 3 can be preformed in a shape that follows the shape of the crystal vibrating piece 6. With these results,
Since the crystal vibrating piece 6 is effectively positioned by the first adhesive 3 and the support spring 15, even if the second adhesive 5 contracts during the final adhesive curing, the crystal vibrating piece is almost deformed. do not do. Therefore, the strain stress is drastically reduced as compared with the conventional one, and the characteristics of the crystal unit are improved. As already described, even if the general support spring 15 is used, the characteristics of the crystal unit can be sufficiently ensured, so that the cost and the thickness of the crystal unit can be reduced.

[0060]

As described above, according to the present invention, it is possible to reduce the thickness of a crystal resonator, improve its characteristics, improve its impact resistance, and reduce its cost.

[Brief description of drawings]

FIG. 1 is a process diagram showing a method of supporting a quartz crystal resonator element according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an example of a completed SMD crystal resonator supporting a crystal resonator element according to the method of the first embodiment of the present invention.

FIG. 3 is a cross-sectional view showing another example of a completed SMD crystal resonator supporting a crystal resonator element according to the method of the first embodiment of the present invention.

FIG. 4 is a diagram showing a method of forming a frequency adjustment vapor deposition pattern on the surface of the quartz crystal resonator element supported by the method of the first embodiment of the present invention.

FIG. 5 is a process drawing showing the method of supporting the quartz crystal resonator element according to the second embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a completed SMD crystal resonator supporting a crystal resonator element according to the method of the second embodiment of the present invention.

FIG. 7 is a cross-sectional view showing a method of supporting a crystal vibrating piece in a conventional SMD crystal resonator.

FIG. 8 is a cross-sectional view showing a method of supporting a crystal vibrating piece in a conventional SMD crystal resonator.

FIG. 9 is a cross-sectional view showing a method of supporting a crystal vibrating piece in a conventional SMD crystal resonator.

FIG. 10 is a cross-sectional view showing a method of supporting a crystal vibrating piece in a conventional SMD crystal resonator.

[Explanation of symbols]

1 substrate 2 escape section 3 First adhesive 4 holding part 5 Second adhesive 6 Crystal vibrating piece 7 Metal wiring 8 protective film 9 Low melting glass 10 cap 11 electrodes 12 masks 13 Frequency adjustment evaporation pattern 15 Support spring 18 Sealant 20 adhesive 22 Buffer spring 25 Second adhesive 26 Corner 27 Moment arrow 28 Strain stress arrow 29 Strain stress arrow

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeshi Murata 4107, Miyota, Miyota-cho, Kitasaku-gun, Kitano, Nagano Prefecture 5 Simeo Precision Co., Ltd. (72) Inventor Hisao Wakabayashi 2-1-1 Nishishinjuku, Shinjuku-ku, Tokyo Chisun Watch Co., Ltd. Head Office (56) Reference JP 62-207008 (JP, A) JP 63-164515 (JP, A) Actual development 61-33521 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) H03H 3/00-3/04

Claims (5)

(57) [Claims] 1. A method of supporting a crystal vibrating piece in which a crystal vibrating piece is supported by a holding portion, the step of applying a first adhesive to the holding portion, and the first bonding applied to the holding portion. A temporary curing step for evaporating the solvent of the agent to make the first adhesive half-cured or more; and a first curing step on the first adhesive.
Applying the second adhesive, and placing the crystal vibrating piece on the holding part so that the end of the crystal vibrating piece comes into contact with the first adhesive and the second adhesive. And an additional second adhesive to secure the end of the crystal vibrating piece.
A step of applying an agent to the end surface of the crystal vibrating piece,
And a step of solidifying the first and second adhesives at a curing temperature, wherein the water is added when the first and second adhesives cure and shrink.
The first adhesive prevents the crystal fragments from rising.
A method for supporting a crystal resonator element, which is characterized in that 2. A method of supporting a crystal vibrating reed in which a crystal vibrating piece is supported by a holding portion, the step of applying a first adhesive to the holding portion, and the first bonding applied to the holding portion. A temporary curing step of evaporating the solvent of the agent to bring the first adhesive into a semi-hardened state or more; a step of applying a second adhesive to an end portion of the crystal vibrating piece; A step of placing the crystal vibrating piece on the holding portion such that an end portion of the quartz vibrating piece contacts the first adhesive; and a step of solidifying the first and second adhesives at a curing temperature , The first and second
And the crystal piece rises when the second adhesive cures and shrinks.
The method for supporting a quartz crystal resonator element , wherein: is prevented by the first adhesive . 3. The first adhesive after the temporary curing step
The shape of is similar to the shape of the end of the crystal resonator element.
The method for supporting a water crystal resonator element according to claim 1 or 2, wherein the method for supporting a water crystal resonator element. 4. The same material as the first adhesive and the second adhesive.
It is an adhesive agent for materials, and is characterized by the above-mentioned.
Method of supporting the quartz crystal vibrating piece. 5. The method according to any one of claims 1 to 4.
Of manufacturing a crystal unit using the method of supporting the mounted crystal resonator element
Law.