JP4443306B2 - Manufacturing method of crystal unit - Google Patents

Description

  The present invention relates to a method of manufacturing a crystal resonator used as a timing device for communication equipment, electronic equipment, and the like.

  Conventionally, crystal resonators have been used as timing devices for portable communication devices and the like.

  As such a conventional quartz resonator, for example, as shown in FIG. 4, a concave portion 22 is formed on the upper surface of a container body 21 made of alumina ceramic or the like, and a quartz resonator element 23 is mounted on the bottom surface of the concave portion 22. A metal lid 24 is attached and bonded on the container body 21 so as to close the opening of the recess 22, and the crystal resonator element 23 is surrounded by the inner surface of the recess 22 and the lower surface of the lid 24. A structure in which the region is hermetically sealed is known (for example, see Patent Document 1).

  In the crystal resonator described above, first, the crystal resonator element 23 is mounted on the bottom surface of the recess of the container body 21 using a conductive adhesive containing a thermosetting resin such as an epoxy resin. The frequency is adjusted, and finally the lid 24 is placed on the upper surface of the container body 21, and the outer periphery thereof is joined to the conductor pattern provided on the upper surface of the container body 21 by a well-known seam welding or the like. Manufactured by.

As a method for adjusting the frequency of the crystal resonator element 23, a predetermined voltage is applied between the vibration electrodes of the crystal resonator element 23 to cause a thickness shear vibration in the crystal resonator element 23, and the frequency is measured. A technique is known in which the surface of the vibrating electrode is scraped off by irradiating the vibrating electrode of the crystal vibrating element 23 with an ion beam until the measured value reaches a predetermined value (see, for example, Patent Document 2).
JP 2001-274649 A JP-A-9-321563

  However, in the above-described conventional crystal unit, it occurs when the conductive adhesive is thermally cured during the manufacturing process, particularly when the crystal resonator element 23 is mounted using a resin conductive adhesive. Siloxane gas or the like may contact the conductor pattern and form an oxide film on the surface of the conductor pattern. In this case, since the bonding material is difficult to wet on the surface of the conductor pattern, it is difficult to bond the lid body 24 to the container body 21 favorably. As a result, poor bonding occurs frequently and the manufacturing yield decreases. Had the disadvantage of

  Therefore, in order to eliminate the above-described drawbacks, a mask that exposes only the surface of the conductor pattern is disposed on the container body 21 before the opening of the concave portion 22 is closed with the lid 24, and then the surface of the conductor pattern is oxidized. It is conceivable to remove the film by dry etching or the like.

  However, when the oxide film on the surface of the conductor pattern is removed as described above, a dry etching process or the like for removing the oxide film is required separately, which causes a disadvantage that the productivity of the crystal resonator element is lowered. .

  The present invention has been devised in view of the above drawbacks, and an object of the present invention is to provide a method for manufacturing a crystal resonator that can increase the manufacturing yield and improve the productivity.

The method for manufacturing a crystal resonator according to the present invention includes a step A of attaching a ring-shaped conductor pattern to the surface of a substrate, and mounting a crystal resonator element having a vibration electrode on the upper surface inside the conductor pattern; Using the mask having a window part that exposes a part or all of each of the vibrating electrode and the conductor pattern while applying a voltage to the quartz vibrating element to cause thickness shear vibration and measuring the frequency thereof , the vibrating electrode The frequency of the crystal resonator element is adjusted by simultaneously irradiating the surface of the conductor pattern and the surface of the conductor pattern with the ion beam, and the oxide film on the surface of the conductor pattern is removed. And a step C of joining a metal lid so as to cover the vibration element.

  According to the method for manufacturing a crystal resonator of the present invention, the frequency of the crystal resonator element is adjusted by simultaneously irradiating the bonding conductor pattern of the vibration electrode surface of the crystal resonator element and the upper surface of the substrate with the ion beam. Since the oxide film on the surface has been removed, the lid can be satisfactorily bonded to the substrate using such a conductor pattern, which can improve the manufacturing yield of crystal units. It becomes.

  In addition, in this case, there is no need to add a separate process to remove the oxide film from the surface of the conductor pattern, so that an increase in man-hours is effectively prevented and the productivity of the crystal unit is maintained high. be able to.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is an exploded perspective view of a crystal resonator manufactured by the manufacturing method of the present invention, and FIG. 2 is a cross-sectional view of the crystal resonator of FIG. 1. The crystal resonator shown in FIG. The container body 1, the crystal resonator element 5, and the lid body 4 are configured.

  The said container body 1 consists of ceramic materials, such as glass-ceramics and an alumina ceramic, for example, the recessed part 1a is provided in the center area | region of the upper surface, and also the upper surface of the container body 1 located outside the opening part of the recessed part 1a A ring-shaped conductor pattern 2 is attached so as to surround the opening of the recess 1a.

  The container body 1 is for housing the crystal resonator element 5 in the recess 1a, and a plurality of external terminals 7 are connected to the lower surface of the container body 1 and a vibration electrode of the crystal resonator element 5 is connected to the bottom surface of the recess 1a. The external terminal 7 functions as a terminal for electrically connecting to the external circuit board when the crystal resonator is mounted on the external circuit board such as a mother board. The external terminal 7 and the mounting pad on the bottom surface of the recess are electrically connected to each other via a wiring conductor on the surface of the container body, a via-hole conductor embedded in the container body, or the like.

  The conductor pattern 2 includes, for example, a nickel layer (thickness: 2 μm to 6 μm) and a gold layer (thickness: 0.7 μm to 1.4 μm) on the upper surface of a metallized layer (thickness: 10 μm to 20 μm) made of tungsten, molybdenum or the like. Are sequentially deposited and formed, and a lower surface of a lid 4 to be described later is bonded to the surface thereof via a bonding material.

  A crystal resonator element 5 is mounted on the bottom surface of the recess 1 a provided on the top surface of the container body 1.

  The quartz vibrating element 5 has a structure in which a pair of vibrating electrodes are attached and formed on both main surfaces of a crystal piece cut along a predetermined crystal axis, and the pair of vibrating electrodes are recessed via a conductive bonding material 6. By being electrically connected to the corresponding mounting pads on the bottom surface, it is mounted on the bottom surface of the concave portion of the container body 1, whereby the crystal resonator element 5 and the container body 1 are electrically and mechanically connected.

  The quartz crystal vibrating element 5 causes thickness-shear vibration at a predetermined frequency when a varying voltage from the outside is applied to the quartz crystal piece via a pair of vibrating electrodes.

  And the cover body 4 is attached to the upper surface of the container body 1 mentioned above so that the opening part of the recessed part 1a may be plugged up.

  The lid 4 is formed so as to have a flat plate shape with a metal such as 42 alloy, Kovar, phosphor bronze, etc., and the outer periphery of the lower surface thereof is joined to the conductor pattern 2 on the upper surface of the container body 1. The crystal resonator element 5 is housed in a region attached to the upper surface and surrounded by the inner surface of the recess 1 a and the lower surface of the lid 4. The lid body 4 and the container body 1 are joined via a brazing material layer 3 having a composition ratio of, for example, 80% gold and 20% tin.

  Further, such a lid 4 is preferably connected to the external terminal 7 for the ground terminal via the wiring conductor of the container body 1, so that the use of the crystal resonator can be performed. At this time, the lid 4 is grounded and a shielding function is provided, and the crystal resonator element 5 can be better protected than an unnecessary electric action from the outside. Therefore, the lid 4 is preferably connected to the external terminal 7 for the ground terminal via the wiring conductor of the container body 1.

  Thus, the above-described crystal resonator applies a fluctuating voltage from the outside between the vibration electrodes of the crystal resonator element 5 via the input / output terminal provided on the lower surface of the container body 1, thereby causing the crystal resonator element 5 to have a predetermined frequency. It functions as a quartz crystal resonator by vibrating it through thickness. An oscillation signal generated and output by an external oscillation circuit based on the frequency of such a crystal resonator is used as a reference signal (clock signal) in an electronic device such as a portable communication device, for example. Become.

  Next, a manufacturing method of the above-described crystal resonator will be described with reference to FIG.

(Process A)
First, the annular conductor pattern 2 is attached to the upper surface of the container body 1 provided with the recess 1a in the central area so as to surround the opening of the recess 1a, and the recess located inside the conductor pattern 2 A crystal resonator element 5 is mounted on the bottom surface of 1a.

  When the container body 1 is made of a ceramic material such as glass-ceramic, for example, a ceramic green sheet obtained by adding and mixing a glass powder, an organic solvent, an organic binder or the like to a ceramic material powder made of alumina ceramics, for example. It is manufactured by applying a conductor paste that becomes a wiring conductor to the surface of the metal by a conventionally known screen printing or the like, laminating a plurality of these to form a laminate, press-molding it, and firing at a high temperature. The In addition, the said recessed part 1a is formed by drilling a substantially rectangular through-hole in the ceramic green sheet distribute | arranged to the upper part of the said laminated body.

  The conductor pattern 2 is formed by applying a conductor paste mainly composed of a metal such as tungsten (W) or molybdenum (Mo) to the upper surface of the container body 1 in a predetermined pattern by screen printing or the like known in the art. After being baked at a high temperature, a nickel (Ni) layer and a gold (Au) layer are sequentially deposited on the surface by a conventionally known electroless plating method, electrolytic plating method or the like.

  On the other hand, the crystal vibrating element 5 has one end of the vibrating electrode provided on both main surfaces thereof facing the mounting pad provided in the concave bottom surface 1 a of the container body 1 with the conductive adhesive 6 interposed therebetween. The conductive adhesive 6 is then heated and cured to be mounted in the recess 1a of the container body 1, whereby the crystal resonator element 5 and the container body 1 are mounted. Are electrically and mechanically connected.

  At this time, a siloxane gas or the like is generated from the conductive adhesive 6 as the conductive adhesive 6 is thermally cured. An oxide film may be formed on the surface.

(Process B)
Next, a predetermined voltage is applied to the quartz crystal vibrating element 5 to cause a thickness shear vibration, and while measuring the frequency, an ion beam is applied to the surface of the vibrating electrode of the quartz crystal vibrating element 5 and the surface of the conductor pattern on the upper surface of the container body. By simultaneously irradiating, the frequency of the crystal resonator element 5 is adjusted and the oxide film on the surface of the conductor pattern is removed.

In the ion beam irradiation described above, a mask having a window portion that exposes part or all of both the vibrating electrode of the crystal vibrating element 5 and the conductor pattern 2 of the container body 1 is disposed on the container body 1. Argon gas is introduced into the inside of the ion gun, and the hot cathode is energized and heated to generate Ar plasma due to direct current discharge between the hot cathode and the anode. On the other hand, an ion beam of Ar ⁺ is generated by applying a voltage. By simultaneously irradiating both the vibrating electrode of the quartz crystal vibrating element 5 and the conductor pattern 2 with this ion beam, the frequency of the quartz crystal vibrator is changed in a direction in which the mass of the vibrating electrode is decreased, and the frequency of the quartz crystal vibrator Is adjusted to have desired characteristics, and an oxide film (metal oxide) formed on the surface of the conductor pattern 2 is scraped off by irradiation of Ar ⁺ , so that the surface of the conductor pattern 2 is used for joining the lid 4. It will be in a suitable state.

  In this case, in order to remove the oxide film from the surface of the conductor pattern 2, it is not necessary to add a separate process as compared with the conventional example. Productivity will be maintained at a high level.

  The removal amount of the conductor pattern 2 by the irradiation of the ion beam has two effects, that is, improvement of wettability of the conductor pattern 2 and prevention of reattachment of a part of the conductor pattern 2 shaved by etching to the surface of the vibrating electrode. From the viewpoint, the thickness from the surface is preferably set to 9 to 130 mm.

(Process C)
Finally, a metal lid 4 is joined to the conductor pattern 2 of the container body 1 so that the crystal resonator element 5 in the recess 1 a is covered, and the opening of the recess 1 a is closed with the lid 4. .

  The lid body 4 is manufactured by adopting a conventionally well-known metal processing method, forming a metal such as 42 alloy into a predetermined shape, and processing the outer shape, and a nickel (Ni) layer, A gold tin (Au—Sn) layer is sequentially deposited. The gold-tin layer functions as the brazing material layer 3 for joining the lid 4 to the container body 1, and the composition ratio of gold-tin is set to, for example, 80% gold and 20% tin, The thickness is set to 10 μm to 30 μm, for example.

  Such a lid body 4 is placed on the container body 1 so as to close the opening of the concave portion 1a, and then the brazing material layer 3 is heated and melted at a high temperature so that the brazing material layer 3 becomes the container. Bonded to the conductor pattern 2 of the body 1, the lid body 4 is attached and fixed to the container body 1, thereby completing a crystal resonator as a product.

  At this time, since the surface of the conductor pattern 2 is in a good state with almost no oxide film by the ion beam irradiation in the process B described above, the wettability of the brazing material 3 with respect to the conductor pattern 2 is very good. Yes, the lid 4 can be reliably bonded to the upper surface of the container body 1. This makes it possible to improve the manufacturing yield of the crystal resonator.

  In addition, this invention is not limited to the above-mentioned embodiment, A various change and improvement are possible in the range which does not deviate from the summary of this invention.

  For example, in the above-described embodiment, the type of crystal vibration element 5 that causes thickness-shear vibration with application of electric power is used, but instead of this type, a surface acoustic wave is generated with application of electric power. Even if the crystal vibrating element 5 is used, the same effect can be obtained.

  In the above-described embodiment, the container body 1 having the concave portion 1a at the center of the upper surface is used as the base body. However, instead of this, a flat substrate having no concave portion may be used as the base body. In this case, the crystal resonator element 5 is mounted in the central area of the upper surface of the substrate, and the annular conductor pattern 2 is deposited and formed on the upper surface of the substrate so as to surround the crystal resonator element 5.

  Further, in the above-described embodiment, the conductor pattern 2 of the base body (container body 1) is directly joined to the lid body 4, but instead, a metal seal ring is attached to the conductor pattern 2. And the lid 4 may be joined to the seal ring by a well-known seam welding or the like.

  Furthermore, in the embodiment described above, it goes without saying that a large number of crystal resonators may be manufactured, or the above-described crystal resonator may be used for a crystal oscillator constituting a part of the whole.

It is a disassembled perspective view of the crystal oscillator manufactured by the manufacturing method of this invention. FIG. 2 is a cross-sectional view of the crystal resonator of FIG. 1. It is sectional drawing for every process for demonstrating the manufacturing method of the crystal oscillator of this invention. It is sectional drawing of the conventional crystal oscillator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Container body 1a ... Concave part 2 ... Conductor pattern 3 ... Brazing material layer 4 ... Lid body 5 ... Quartz crystal vibration element 6 ... Conductive adhesive 7 ... External Terminal

Claims (1)

A process of attaching an annular conductor pattern to the surface of the substrate and mounting a crystal resonator element having a vibration electrode on the upper surface inside the conductor pattern; and
Using the mask having a window portion that exposes part or all of the vibrating electrode and the conductor pattern while applying a voltage to the quartz crystal vibrating element to cause vibration and measuring the frequency , the vibration The step of simultaneously adjusting the frequency of the crystal resonator element by simultaneously irradiating the surface of the electrode and the surface of the conductor pattern with the ion beam, and removing the oxide film on the surface of the conductor pattern;
And a step C of bonding a metal lid so as to cover the crystal resonator element with respect to the conductor pattern.

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