JP2007300418A - Manufacturing method of lame-mode crystal resonator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of improving the mechanical strength of a Lame-mode crystal resonator as a whole, with respect to the shape of the Lame-mode crystal resonator, in particular, realization of size reduction, high accuracy, and a low CI value. <P>SOLUTION: The manufacturing method of the Lame-mode crystal resonator for solving aforementioned tasks includes the steps of joining a crystal wafer to a glass material; thinning the thickness of the crystal wafer, in a state where the crystal wafer and the glass material are incorporated; forming an external shape in the integrated state when the thickness of the crystal wafer reaches a desired thickness; exfoliating the crystal wafer and the glass material that have integrated; and forming an exciting electrode for the crystal wafer to the crystal wafer, and a mechanical polishing method is adopted for the processing of thinning the thickness of the crystal wafer and an etching processing process is adopted for forming the exciting electrode. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is to obtain a resonator shape of a lame mode crystal resonator, and in particular, to improve the device mounting structure for realizing miniaturization and high accuracy, and to maintain the electrical characteristics of the device. However, the present invention relates to a method for manufacturing a lame mode crystal resonator having improved holding strength and simplification during mounting against dropping and impact.

  The lame mode crystal resonator is small and can obtain an optimum vibration mode for realizing a low frequency. Therefore, the realization of miniaturization while being a low-frequency vibrator has a large market widely used for mobile phones, portable small game devices and the like that have made remarkable progress in recent years.

  The lame mode crystal unit is formed of a piezoelectric substrate with a thickness of several tens of μm. In order to hold the lame mode crystal unit, there is a rotational moment but no displacement so as not to hinder vibrations. It is common to keep clauses. As shown in FIG. 6, it is supported and held through the connecting portions at the four corners. From this node, the arm is pulled out and connected to the holding portion, and mounted on the package via the connecting portion and assembled to obtain a vibrator. At this time, by making the arm portion as thin as possible, the inhibition of vibration can be reduced and the equivalent series resistance can be reduced. Therefore, a strong structure is required at the time of drop impact.

  In short, conventionally, when a vibrator is manufactured, support portions are provided at the four corners of a square serving as a node of vibration in order to avoid an increase in the equivalent resistance value R1, and accordingly, the vibration portion, the support portion, Since the connecting portions are integrally formed, moment forces are generated at the four corners that are vibration nodes. Therefore, if the support portion is not properly designed, vibration energy leaks to the support portion and the equivalent resistance value R1 becomes large. Furthermore, in order to reduce the equivalent resistance value R1, in order to reduce the increase in the equivalent resistance value R1, if the width and thickness of the support part from the four corners are reduced, it may be affected by an impact such as dropping or an excessive excitation current. There is a risk of damage if the amplitude increases.

  As described above, when the lame mode crystal resonator is a square plate, it is a vibration mode in which the four corners are nodes (rotation nodes) and vibrate in the same volume in the plane. In order to obtain a vibrator having a good (low) equivalent resistance value R1, it is the most effective support method to pull out the support portions from the four corners which are the nodes of vibration. The actual support method is as follows. At present, it is fixed to a substrate such as ceramic using a conductive adhesive via a connecting portion.

  An example of the above-described process is shown in FIG. 7, and a series of wafer cleaning, light etching, protective vapor deposition film (CrAu), resist coating, exposure, development, patterning, etching, resist stripping, CrAu stripping, cleaning, and excitation electrode deposition In this process, an element is formed and mounted on a package made of a ceramic material or the like with a conductive adhesive to obtain a lame mode crystal resonator.

JP 2003-142979 A JP 2001-31537 A JP 2004-242256 A JP, 2005-244702, A In addition to the prior art literature specified by the above-mentioned prior art literature information, the applicant did not find the prior art literature relevant to the present invention by the time of this application.

  Since the conventional lame mode quartz crystal resonator described above is a rectangular plate with an integer ratio of the vibration part, for example, when supporting the four corners of the vibration part, the vibration nodes are the four corners and the vibration displacement is small. The vibration of the lame mode due to the holding of the vibration part is not hindered.

  However, since the vibration part, the support part, and the connection part are integrally formed, when the lame mode crystal resonator is mounted and stored in the container, the part that connects the vibration part and the support part has a lame mode vibration. Since the moment force generated from this node is generated, bending vibration is generated in the connection portion under the influence of the moment force.

  Therefore, if the shape of the support part and the connection part is not set to appropriate design values, vibration of the vibration part will occur, and unnecessary vibration will be transmitted to the support part and connection part that hold the vibration part. There is a risk that the vibrations of the

  In addition, in order to mount the vibrating part on the container by some means, a support part and a connection part are required. For this reason, when considered in the form of a vibrator, a structure in which a support part and a connection part are integrated in addition to the vibration part is required, so that it is difficult to reduce the overall size. On the other hand, in order to promote downsizing, it is possible to maintain a high Q value by reducing the weight of the supporting part other than the vibrating part and making it fragile. At present, it is difficult to keep the impedance (CI value) of the vibrator low.

  Therefore, a technique for suppressing the CI value by reducing only the vibration part is known. In that case, there is a description that uses a powder beam to realize vibrator thickness processing and a chemical etching method, but since powder beam is a mechanical processing process, it is difficult to reduce costs in the manufacturing process, Considering the processing time, it is expected that a lot of processing time will be required for mass production. In addition, it is conceivable that making only the vibration part thin may cause insufficient mechanical strength, and there is a problem that it is difficult to withstand practical use.

  Therefore, the present invention provides a rectangular crystal element having an electric charge applied thereto, with the four corners of the crystal element serving as nodes, and when extending in the longitudinal direction of the rectangular shape, expands and contracts in the lateral direction, and A lame-mode crystal vibration consisting of an LQ1T-cut or LQ2T-cut quartz substrate, which forms a contour vibration that expands and contracts in the longitudinal direction when it extends in the short direction of the rectangular shape. In the manufacturing method of the child, the step of bonding the crystal wafer and the glass material, the step of reducing the thickness of the crystal wafer in a state where the crystal and the glass material are integrated, and the crystal wafer having a desired plate thickness Then, the step of forming the outer shape in the integrated state, the step of separating and separating the glass wafer and the glass material, and the excitation of the lame mode vibrator on the crystal wafer. A method of manufacturing a lame mode crystal resonator, comprising: a step of forming an electrode, wherein a mechanical polishing method is used for thinning a quartz wafer and an etching process is used for forming an excitation electrode It is.

  In short, according to the present invention, a quartz wafer and a glass material are bonded together, and the thickness of the quartz wafer, that is, the quartz element is reduced in an integrated state. When the quartz wafer is thinned to the desired thickness, the glass material is peeled off, the excitation electrode is formed on the surface of the quartz element, and then separated into individual lame mode quartz crystal units to form a lame mode quartz crystal. By doing so, the problem of the prior art was improved by significantly reducing the damage of the quartz crystal element during the manufacturing process especially during the thickness processing.

  As described above, in the method of manufacturing a lame mode crystal resonator according to the present invention, the manufacturing method with improved overall mechanical strength is used to improve the yield in the manufacturing process and reduce the manufacturing cost. As a result, the quality of the lame mode crystal resonator can be improved.

Embodiments of the present invention will be described below with reference to the drawings. In each figure, the same numerals indicate the same objects.
A crystal element 1 having a piezoelectric element plate as a substrate. When one dimension of the side ratio of the substrate is 1 (L), the other corners of the plate satisfy an integer ratio (1 (L) to n). The feature of the lame mode vibrator is that it has no vibration part. In the case of a square plate as shown in FIG. 1, when the two sides A facing each other with the corners at the four corners are displaced toward the center of the square, the other two sides B are displaced outwardly of the square, and the two sides facing each other When A is displaced in the outward direction of the square, the other two sides B are in a vibration form that is displaced in the center direction of the square.

  Therefore, it vibrates in the form of repeating the operations of FIG. 1 (a) and FIG. 1 (b). This FIG. 1 is called a primary vibration mode of a square plate. FIG. 1C shows a dimensional concept of the diaphragm. FIG. 2 shows a schematic diagram of the vibration mode. FIG. 3 shows an example of a high-order vibration mode based on the basic shape. The concept is the same as the basic form of FIG. 1, FIG. 3 (a) shows the case of the secondary (mode), and FIG. 3 (b) shows the case of the tertiary (mode). In FIG. 1 and FIG. 3, the Δ mark represents the non-vibrating part of the lame mode vibrator 2.

  Here, the flow of the manufacturing process of the present invention is shown in FIG. When a charge is applied to the rectangular crystal element 1, the four corners of the crystal element 1 are nodes, and when extending in the longitudinal direction of the rectangular shape, it expands and contracts in the short direction, and the rectangular short direction In a manufacturing method of a lame mode quartz crystal resonator comprising a quartz substrate of LQ1T cut or LQ2T cut, which produces a vibration form of contour vibration that expands and contracts in the longitudinal direction when it is stretched in the direction of A step of bonding the quartz wafer and the glass material, a step of reducing the thickness of the quartz wafer in a state where the quartz crystal and the glass material are integrated, and the integration of the quartz wafer when the quartz wafer has a desired plate thickness. A step of forming an outer shape in a state, a step of peeling and separating the glass wafer and the glass material, and a step of forming an excitation electrode of the lame mode vibrator 2 on the crystal wafer. Made, using a mechanical polishing method for processing of thinning the plate thickness of the crystal wafer, the outer shape forming is a manufacturing method of the Lame mode quartz crystal resonator characterized by using an etching process.

As an actual processing method, an element is formed in a series of processes including wafer cleaning, light etching, protective vapor deposition film (CrAu), resist coating, exposure, development, patterning, etching, resist stripping, CrAu stripping, cleaning, and excitation electrode deposition. Although formed, the main point of the present application is to reduce the plate thickness of the quartz wafer by a polishing apparatus as an example of laminating the quartz wafer and the glass material integrally.
In this case, a technique such as direct bonding is used for bonding the quartz wafer and the glass material, but there is no particular limitation. When the quartz wafer has been thinned to a desired thickness, a resist is formed on the quartz wafer and an outer shape is formed by etching to obtain the outer shape of the lame mode crystal resonator. Further, although the excitation electrode (including the extraction electrode) is formed on the quartz wafer by vapor deposition, the overall conceptual diagram is not shown here.

Regarding the change in the shape of the crystal element 1 obtained in the manufacturing process of the above flow, in FIG. 5A, in the crystal wafer in a state where the crystal wafer and the glass material are united with each other, Reduce the thickness. Glass material is reinforced to improve cracking in the process of thinning the quartz element.
Subsequently, as shown in FIG. 5B, when the desired plate thickness is reached, the outer shape is formed in an integrated state, and then the integrated quartz wafer and glass material are separated and separated. Thereafter, as shown in FIG. 5C, excitation electrodes constituting the lame mode crystal resonator 2 are formed on the front and back of the crystal element to complete the lame mode resonator 2.

  By improving the mechanical strength of the quartz element 1 in the process of reducing the thickness of the quartz element, the vulnerability of the element of the lame mode quartz crystal resonator 2 was improved, and the damage of the element during the manufacturing process was improved. Mechanical strength can be improved.

It is a top view which shows the primary form of a lame mode crystal oscillator. It is a schematic diagram of the vibration mode shown in FIG. It is a top view which shows the vibration form in the case of a high-order mode based on the basic form of FIG. It is a flowchart which shows the flow of manufacture of the lame mode vibrator | oscillator of this invention. It is a conceptual diagram of the element shape obtained by the flow of element formation of this invention. It is a conceptual diagram of the lame mode crystal resonator form shown as a conventional example. It is a flowchart which shows the manufacturing process which forms the element of a lame mode vibrator.

Explanation of symbols

1 Crystal element 2 Lame mode crystal resonator

Claims (2)

When a charge is applied to a rectangular crystal element, the four corners of the crystal element are nodes, and when extending in the longitudinal direction of the rectangular shape, the rectangular crystal element expands and contracts in the short direction, and the rectangular short shape A method for manufacturing a lame mode quartz crystal resonator comprising an LQ1T-cut or LQ2T-cut quartz substrate, which generates a vibration pattern of contour vibration that expands and contracts in the longitudinal direction when stretched in the direction, and comprises a vibrating part, a supporting part, and a connecting part. And
The step of bonding the crystal wafer and the glass material, the step of reducing the thickness of the crystal wafer in a state where the crystal and the glass material are integrated, and the integrated state when the crystal wafer has a desired plate thickness A method of manufacturing a lame mode quartz crystal resonator, comprising: forming an outer shape with the step of: separating and separating the integrated quartz wafer and glass material; and forming an excitation electrode on the quartz wafer. 2. The method of manufacturing a lame mode crystal resonator according to claim 1, wherein a mechanical polishing method is used for processing to reduce the thickness of the quartz wafer, and an etching process is used for forming the excitation electrode.

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