JP4855816B2 - Method for manufacturing a lame mode crystal resonator - Google Patents

Description

The present invention relates to a method for manufacturing a lame mode crystal resonator, and more particularly, to a method for improving the mechanical strength of the entire lame mode crystal resonator by realizing miniaturization, high accuracy, and low CI value. It is.

  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 in 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 design of the support portion is not appropriate, vibration energy leaks to the support portion, and the equivalent resistance value R1 increases. 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. A series of wafer cleaning, light etching, protective vapor deposition film (CrAu), resist coating, exposure, development, patterning, etching, resist stripping, CrAu stripping, cleaning, excitation electrode deposition An element is formed in the process, and is 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 the node is generated, bending vibration is generated at the connecting 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 the thickness processing of the vibrator and a chemical etching method, but since the powder beam is a mechanical processing process, it is difficult to reduce the cost 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 is such that 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 contracts in the short direction, and the rectangular element An LQ1T-cut or LQ2T-cut quartz substrate that produces a vibration form of contour vibration that shrinks in the longitudinal direction when it extends in the short direction of the shape. In the manufacturing method, a step of bonding a flat plate of glass to the main surface of the crystal element, a step of removing all glass except the connection portion of the crystal element, a step of patterning the crystal element, A method for manufacturing a lame mode quartz crystal resonator comprising a step of forming an electrode on a crystal element. At this time, a wet etching method is used for the glass removing step and the step of patterning the crystal element.

  Therefore, the inventor of the present application has searched for the most efficient processing conditions for the etching conditions of the glass and the crystal element. In addition, the present inventor has improved the support structure of the lame mode quartz crystal resonator to date, and has improved the maintenance of various electrical characteristics, and maintained and improved the mechanical strength and impact resistance strength of the lame mode crystal resonator. Realization has improved the conventional problems.

As described above, by using the manufacturing method of the lame mode crystal resonator of the present invention, while improving the mechanical strength of the connecting portion, which is a component of the lame mode crystal resonator, the original electrical characteristics are not improved. The production of the lame mode crystal resonator can be realized without any influence. As a result, the yield in the manufacturing process can be improved, and the manufacturing cost can be reduced and the time required for mass production can be reduced.

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. 1A and FIG. This FIG. 1 is called the lowest order 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). 1 and 3 indicate a non-vibrating portion of the lame mode vibrator.

FIG. 4 shows a conceptual shape of the lame mode crystal resonator of the present invention. 4A is a perspective view, and FIG. 4B is a partial cross-sectional view taken along the line AA. When a charge is applied to a rectangular crystal element, the four corners of the crystal element are nodes, and when it extends in the longitudinal direction of the rectangular shape, it contracts in the lateral direction and extends in the rectangular lateral direction. Connection of crystal elements in a lame mode crystal resonator composed of an LQ1T-cut or LQ2T-cut quartz substrate that sometimes produces a vibration form of contour vibration that shrinks in the longitudinal direction, which is composed of a vibration part 1, a support part 2, and a connection part 3 It is drawn that it has a form in which four glass materials are joined to the part. In FIG. 4A, the shape of the support portion is an example, and the same effect can be obtained even with other support shapes.

FIG. 5 shows a flow chart for obtaining the element outline of the lame mode crystal resonator of the present invention. As a method for obtaining the above-mentioned lame mode crystal resonator, when a charge is applied to a rectangular crystal element, the corners of the four corners of the crystal element are nodes, and when extending in the longitudinal direction of the rectangular shape, It consists of a quartz substrate of LQ1T cut or LQ2T cut that produces a vibration form of contour vibration that shrinks and contracts in the longitudinal direction when it extends in the short direction of the rectangular shape. In the manufacturing method of the lame mode crystal resonator to be configured, the step of bonding the flat plate of the glass 4 to the main surface of the crystal element, the step of removing all the glass 4 except the connecting portion of the crystal element, This is a method for manufacturing a lame mode quartz crystal resonator comprising a patterning step and a step of forming an electrode on a quartz element.

  At this time, a wet etching method is used for the glass 4 removal step and the patterning step for the crystal element. However, the wet etching solution used for partially removing the glass 4 and the crystal element patterning are performed. Since the processing speeds of the wet etching liquid used in the above are different from each other, when the glass 4 is processed, a liquid having a lower wet etching liquid concentration than that used for processing the crystal element is used. In addition, in the process mentioned above, the process of obtaining the element shape of the lame mode crystal resonator other than the process related to the bonding with the glass 4 flat plate is formed according to the conventional process.

It is a top view which shows the primary form of a lamé mode crystal oscillator. This is a mode for analyzing the vibration form shown in FIG. It is a top view which shows the vibration form in the case of a higher order based on the basic form of FIG. It is a perspective view which shows the form of the lame mode vibrator | oscillator of this invention. It is a flowchart 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

DESCRIPTION OF SYMBOLS 1 Vibration part 2 Support part 3 Connection part 4 Glass

Claims (2)

When a charge is applied to the rectangular crystal element, the corners of the four corners of the crystal element are nodes, and when extending in the longitudinal direction of the rectangular shape, it contracts in the short direction, and the rectangular short direction resulting in vibration form of contour vibration shrinks in the longitudinal direction when elongated in, LQ1T cut or made from a quartz substrate LQ2T cut vibrating portion, the supporting portion, the manufacturing method Oite of Lame mode quartz crystal resonator constituting the connection portion,
A step of bonding a flat plate of glass to the main surface of the crystal element, a step of removing all glass except the connection portion of the crystal element, a step of patterning the crystal element, and an electrode on the crystal element A method of manufacturing a lame mode quartz crystal resonator, comprising: 2. The method of manufacturing a lame mode crystal resonator according to claim 1, wherein a wet etching method is used for the glass removing step and the step of patterning the crystal element.

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