JP3824356B2 - How to hold quartz crystal resonator element - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a substrate provided with a step, and a method for holding a crystal vibrating piece in which one end is fixed to an upper surface of the step by an adhesive and the other end is free.
[0002]
[Prior art]
As a surface-mount type crystal resonator widely used as various piezoelectric elements, piezoelectric oscillators, piezoelectric filters, etc., the one shown in FIG. 6 has been known. This is because a package base 2 having shoulder surfaces 1a and 1b on both sides of the inside, an electrode portion 3 formed on one shoulder surface 1a, and a crystal spanned between both shoulder surfaces 1a and 1b of the package base 2. The vibrating piece 4 is composed of a conductive adhesive 5 for fixing one end 4a of the quartz crystal vibrating piece 4 to the electrode portion 3 after being stretched, and a flat cap 7 for hermetically sealing the inside of the package base 2. .
[0003]
In the crystal resonator having such a configuration, only one end 4a of the crystal vibrating piece 4 is fixed and the other end 4b side is free. Therefore, when both ends of the crystal vibrating piece 4 are fixed, In comparison, the stress generated in the crystal vibrating piece 4 due to fixing to the package base 2 can be suppressed, and the performance can be improved. However, since the other end 4b of the crystal vibrating piece 4 is always in contact with the shoulder surface 1b of the package base 2, the stress inside the crystal vibrating piece 4 cannot be completely removed.
[0004]
Therefore, conventionally, as shown in FIG. 7, when the one end 4 a of the crystal vibrating piece 4 is fixed to the one surface 1 a by the conductive adhesive 5, the other end 4 b of the crystal vibrating piece 4 and the shoulder of the package base 2. In some cases, the spacer 6 is sandwiched between the surface 1b, the conductive adhesive 5 is cured, the spacer 6 is removed, and the other end 4b of the crystal vibrating piece 4 is completely free as shown in FIG. (A similar technique is disclosed in JP-A-8-186457).
[0005]
[Problems to be solved by the invention]
However, the holding structure for the quartz crystal vibrating piece 4 requires an operation for inserting and removing the spacer 6 and may cause damage to the quartz crystal vibrating piece 4 when the spacer 6 is removed. There was a problem. In addition, a certain amount of clearance h1 is required between the quartz crystal resonator element 4 and the cap 7, but the crystal oscillator is sufficiently thinned by separating the other end 4b of the crystal oscillator 4 from the one surface 1b. I couldn't.
[0006]
Therefore, the present invention aims at cantilevering the quartz crystal vibrating piece in a simple manufacturing process without using a spacer or the like, and at the same time reducing the thickness of the finished quartz crystal resonator.
[0008]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a method for holding a quartz crystal resonator element comprising: a flat plate crystal resonator element in which one end of a crystal oscillator piece is fixed to an upper surface of a step provided on a substrate by an adhesive and the other end is free. In the holding method, an adhesive is applied to the upper surface of the step of the substrate, one end of the crystal vibrating piece is placed on the adhesive, and the crystal vibrating piece is inclined between the upper surface corner and the lower surface of the step. And a step of solidifying the adhesive to fix one end of the crystal vibrating piece, and the crystal vibrating piece using the upper surface corner as a fulcrum by curing shrinkage of the adhesive when the adhesive is solidified. The other end is slightly spaced from the lower surface of the step.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a crystal resonator and a method for holding a crystal resonator element according to the present invention will be described in detail with reference to the accompanying drawings. As shown in FIGS. 1 and 2, the crystal resonator according to this embodiment includes a rectangular package base 10, and a flat plate crystal resonator element 11 housed in an inclined state in the package base 10. The cap 12 covers the upper part of the crystal vibrating piece 11 and hermetically seals the inside. A package base 10 as a substrate has a box shape, and an internal space is formed by an inner bottom surface 13 and a peripheral wall 14 surrounding the periphery. Further, a step portion 15 is formed on one side of the inner bottom surface 13, and a pair of electrode portions 16 a and 16 b are formed on the upper surface of the step portion 15. The crystal vibrating piece 11 is cantilevered via the conductive adhesive 17 applied on the electrode portions 16 a and 16 b, and the crystal vibrating piece 11 is interposed between the upper surface of the step portion 15 and the inner bottom surface 13. Placed in an inclined state. In this embodiment, one end 11a of the crystal vibrating piece 11 is fixed to the conductive adhesive 17, and the other end 11b is slightly separated from the inner bottom surface 13 to be in a free state. The dimension d between the inner bottom surface 13 of the package base 10 and the upper surface of the step portion 15 is suitably about 0.05 to 0.5 mm, and the distance between the other end 11b of the crystal vibrating piece 11 and the inner bottom surface 13 is appropriate. The distance k is extremely small and is at most less than the dimension d.
[0010]
Note that the upper surface of the package base 10 is covered with a cap 12 via an adhesive to hermetically seal the internal space, but the other end 11b of the crystal vibrating piece 11 is inclined downward, A clearance h2 between the cap 12 and the cap 12 can be provided, and the package can be made thinner. Moreover, although the case where the box-shaped package base 10 is used as the substrate has been described in the above embodiment, the shape of the substrate in the present invention is not limited at all.
[0011]
Next, a method for holding the crystal vibrating piece 11 will be described. 3 to 5 show the steps of the holding method. As described above, the package base 10 has the step portion 15 on one side of the inner bottom surface 13, and includes the electrode portions 16 a and 16 b on the upper surface thereof. In the first step, as shown in FIG. 3, a conductive adhesive 17 is applied on the electrode portions 16a and 16b. Various application methods can be employed, such as using a dispenser that operates by screen printing or air pressure.
[0012]
In the second step, as shown in FIG. 4, one end 11 a of the crystal vibrating piece 11 is placed on the electrode portions 16 a and 16 b coated with the conductive adhesive 17, while the other end of the crystal vibrating piece 11 is placed. 11b is placed on the inner bottom surface 13 of the package base 10, and the crystal vibrating piece 11 is placed in an inclined state. Therefore, in the vicinity of the one end 11a of the crystal vibrating piece 11, the state comes into contact with the upper surface corner 18 of the step 15 as shown in FIG.
[0013]
In the third step, the package base 10 on which the crystal vibrating piece 11 is placed is placed in a curing furnace to cure the conductive adhesive 17. Since the conductive adhesive 17 is an epoxy thermosetting adhesive, it contracts due to a cross-linking reaction between molecules when it is cured. The shrinkage amount of the conductive adhesive 17 at that time is proportional to the thickness t of the conductive adhesive 17 interposed between the crystal vibrating piece 11 and the electrode portions 16a and 16b, and as shown in FIG. As the thickness t gradually increases as the distance from the top corner 18 increases, the amount of contraction at the end increases, and as shown in FIG. Slightly turns counterclockwise as a fulcrum. The rotation of the crystal vibrating piece 11 slightly lifts the other end 11b of the crystal vibrating piece 11 that has been in contact with the inner bottom surface 13 of the package base 10, and a gap 19 is formed between the package bases 10 as shown in FIG. . Then, when the conductive adhesive 17 is cured from the curing furnace, the state of FIG. 2 is maintained, and the other end 11b of the crystal unit 11 becomes completely free. In addition, since the conductive adhesive 17 has a specific value for the shrinkage rate of the conductive adhesive 17, the size of the gap 19 should be adjusted according to the type of conductive adhesive 17 and the amount of coating. Can do.
[0015]
【The invention's effect】
As described above, according to the method for holding a quartz vibrating piece of the present invention according to claim 1 , the quartz vibrating piece is cantilevered by utilizing the contraction when the conductive adhesive is cured as described above. Therefore, the manufacturing process is extremely simple, and the quartz resonator can be easily made thin.
[Brief description of the drawings]
FIG. 1 is a cross-sectional perspective view showing an embodiment of a crystal resonator according to the present invention.
FIG. 2 is a cross-sectional view of the crystal resonator.
FIG. 3 is a cross-sectional view showing an adhesive application process.
FIG. 4 is a cross-sectional view showing a step of placing a crystal vibrating piece.
FIG. 5 is an explanatory view showing rotation of a quartz crystal vibrating piece due to contraction of a conductive adhesive.
FIG. 6 is a cross-sectional view showing an example of a conventional crystal resonator.
FIG. 7 is a cross-sectional view when a spacer showing another example of a conventional crystal unit is sandwiched.
FIG. 8 is a cross-sectional view when the spacer is removed from the conventional crystal unit.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Package base 11 Crystal vibrating piece 13 Internal bottom face 15 Step part 17 Conductive adhesive 19 Crevice

Claims (1)

In the holding method of the flat plate-like crystal vibrating piece in which one end of the crystal vibrating piece is fixed to the upper surface of the step provided on the substrate with an adhesive and the other end is free.
A step of applying an adhesive on the upper surface of the step of the substrate, a step of placing one end of the crystal vibrating piece on the adhesive and disposing the crystal vibrating piece obliquely between the upper surface corner and the lower surface of the step; A step of solidifying the adhesive and fixing one end of the quartz crystal vibrating piece,
A method of holding a quartz crystal vibrating piece, wherein the other end of the quartz crystal vibrating piece is slightly spaced from the bottom surface of the step with the upper surface corner as a fulcrum by curing shrinkage of the adhesive when the adhesive is solidified.

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