JP5005251B2 - Method for manufacturing a lame mode crystal resonator - Google Patents

Description

  The present invention relates to a resonator shape of a lame mode crystal resonator, and more particularly, to a manufacturing method that realizes downsizing, high accuracy, and a low CI value and improves the mechanical strength of the entire lame mode crystal resonator. 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, 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 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 provided with a crystal element having a main surface of a rectangular shape with LQ1T cut or LQ2T cut, and the ratio of the length of the long side to the length of the short side on the main surface of the crystal element is the length of the short side. , The length of the long side is an integer greater than or equal to 2 , and when a charge is applied to the crystal element, the non-displaced part generated at the corner and the long side of the crystal element is saved. In the manufacturing method of a lame mode quartz crystal resonator that generates a vibration form of contour vibration as a crystal wafer in a crystal wafer in which a plurality of the crystal elements are arranged in a matrix in the vibration region of each crystal element A step of forming a convex holding portion in a portion that becomes a non-displacement portion without a rotational moment using an etching process, and a step of cutting and dividing the crystal wafer by a dicing method to form individual crystal elements. Preparation A method for producing a Lame mode quartz crystal resonator, characterized in that the.

  In short, the present invention does not process and form the lame mode crystal resonator individually, but processes it in a form in which a plurality of crystal elements are obtained in a single crystal wafer state. At this time, since the holding strength of the crystal element, that is, the lame mode crystal resonator mounted in the container is ensured, the mechanical strength in the form of the lame mode crystal resonator is improved. Improved the conventional problem.

  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. In addition, 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 a non- displacement portion. 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. At this time, the center and the corner of the main surface of the quartz base plate 1 are not displaced. A portion where no displacement occurs during the lame mode vibration in the crystal element 1 is called a non-displacement portion.

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. And FIG.
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 idea is the same as the basic form of FIG. 1, and FIG.
Indicates a secondary (mode) case, and FIG. 3 (b) shows a tertiary (mode) case. 1 and 3 indicate a non- displacement portion of the lame mode vibrator.

Here, the flow of the manufacturing process of the present invention is shown in FIG. An LQ1T cut or an LQ2T cut is provided with a crystal element 1 whose main surface has a rectangular shape, and the ratio of the length of the long side to the length of the short side of the main surface of the crystal element 1 is set to 1. In this case, the length of the long side is an integer of 2 or more, and when the crystal element 1 is charged, the contour vibration is generated using the non-displaced portions generated at the corner and the long side of the crystal element 1 as nodes. In the manufacturing method of the lame mode quartz crystal resonator 3 that generates the above-described vibration form, the rotational moment within the vibration region of each crystal element 1 in the crystal wafer in which a plurality of crystal elements 1 are arranged in a matrix A step of forming a convex holding portion 2 in a portion that becomes a non-displaceable portion without using an etching process, and a step of cutting and dividing a crystal wafer by a dicing method to form individual crystal elements 1. LA characterized by Memodo is a method for manufacturing a quartz oscillator 3.

  Actual processing methods include wafer cleaning, light etching, protective vapor deposition film (CrAu), resist coating, exposure, development, patterning, etching, resist stripping, CrAu stripping, cleaning, and excitation electrode deposition. 2 is also formed, but the main point of the present application is that the convex portion is formed by half etching so that the convex holding portion 2 can be formed in the non-displaceable portion in the vibration region of the quartz crystal element 1 without the rotational moment on one crystal wafer. It is formed.

  About the shape of the crystal element 1 obtained by the manufacturing process of said flow, the outline | summary is demonstrated with the perspective view of FIG. FIG. 5A shows a crystal element 1 as a base of the lame mode crystal resonator 3, which is a part of a single wafer (a part of FIG. 5B). Etching is performed at. The convex holding portion 2 is formed on at least one surface formed in the non-displacement portion in the vibration region, and the detailed size of the holding portion 2 varies depending on the output frequency of the lame mode crystal resonator.

  FIG. 5B is a conceptual diagram showing the state of one wafer, and a plurality of crystal elements 1 shown in FIG. 5A are arranged in a matrix. The crystal element 1 shown in FIG. 5A is a part thereof, and the convex holding portion 2 is performed on all the crystal elements 1 in the form of a single wafer by simultaneous processing, and FIG. As shown, the crystal element 1 is divided by dividing (dicing process) into one unit of the lame mode crystal resonator 3.

  The divided crystal element 1 is accommodated in a manner that the holding part 2 matches the container part, and the holding part 2 is formed with a part of the extraction electrode from the excitation electrode formed on the crystal element 1. The structure is such that conduction is achieved by the receiving part of the container body that is fitted to the holding part 2.

  Since the crystal element 1 is formed by the process of dividing one crystal wafer individually, it can be manufactured more efficiently than the case where it is formed individually. In addition, it is easy to distinguish the case where each crystal element 1 is formed by etching because it is divided from one crystal wafer by a dicing method, and the end face state of the crystal element 1 is made different. The manufacturing method can be identified.

  In the present invention, since a plurality of crystal elements 1 are processed in a single crystal wafer state and the support form of the crystal elements 1 holds a non-displacement portion without a rotational moment in the vibration region, 1. Since the holding strength in a state where the lame mode crystal resonator 3 is mounted on the container is ensured, the mechanical strength in the form of the lame mode crystal resonator 3 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 form obtained by the flow of element formation of the present 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 Crystal element 2 Holding part 3 Lame mode crystal oscillator

Claims (1)

With LQ1T cut or LQ2T cut, the main surface has a rectangular crystal element,
When the ratio of the length of the long side to the length of the short side on the main surface of the crystal element is 1, the length of the long side is an integer of 2 or more,
In the manufacturing method of the lame mode crystal resonator in which when the electric charge is applied to the crystal element, the vibration form of the contour vibration is generated with the non-displacement portions generated at the corners and long sides of the crystal element as nodes.
In a quartz wafer in which a plurality of quartz crystal elements are arranged in a matrix, a convex holding portion is etched at a location where there is no rotational moment in the vibration region of each quartz crystal element. Forming using a process;
And a step of cutting and dividing the crystal wafer by a dicing method to form individual crystal elements.

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